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SpawnKit — spawn any creature, anywhere

SpawnKit is a kit for Outward that spawns creatures at runtime as real vanilla hostiles — and an in-game menu that lets you do it yourself. Press \ (backslash), pick a creature, and it appears beside you. It's for players who want to stage fights, and for modders who want a one-line creature spawn.

Alpha. The core spawn / despawn / AI loop is solid, but you will hit rough edges (see Known limitations): roughly a quarter of the creature roster can't be fetched yet, spawning is host-driven in co-op, and there's an occasional cosmetic terrain glitch. Back up saves you care about before experimenting.

At a glance - Type: gameplay tool + reusable library (kit) - GUID: cobalt.spawnkit - Requires: BepInEx 5 (Outward's Mono branch), plus ForgeKit, DonorKit, CompanionKit, NetKit, and AggroKit (CompanionKit pulls it in) - Config: BepInEx/config/cobalt.spawnkit.cfg - Commands: BepInEx/config/SpawnKit_cmd.txt

For players

SpawnKit gives you a real vanilla hostile — not a dummy or a stand-in. It wanders, it aggros, it fights, it drops its normal loot, and it dies like the wild version, because it is the wild version. Spawn a pack of hyenas to train on. Drop a Tuanosaur next to a bandit camp and watch them fight each other. Restock a region you've already cleared out.

Spawns are ephemeral: they never enter your save file, and they vanish when you leave the area.

Using the menu

Launch the game, load a save, and press \ (backslash) for a draggable window listing every creature you can spawn.

  • ● means the creature is ready — it spawns instantly.
  • ○ means it's cold: the first spawn pauses 1–6 seconds while SpawnKit fetches its body (see How it works). Click Prewarm to pay that cost up front instead.
  • Set a count, hit Spawn, and use Despawn All / Kill All to clean up.

The key is rebindable ([Menu] MenuKey, default Backslash — a classic debug-menu choice). The menu closes on Esc, on \ again, or when you open a vanilla menu.

Installing

Installing through a mod manager pulls in every dependency automatically. By hand, drop SpawnKit and its dependency kits — ForgeKit/, DonorKit/, AggroKit/, NetKit/, CompanionKit/, SpawnKit/ — side by side into BepInEx/plugins/. If BepInEx logs a dependency error and refuses to load SpawnKit, one of the others is missing. See Installing for the full setup.

How it works

Outward has no way to create a creature from nothing — every creature is baked into the scene it lives in. So SpawnKit borrows one: it quietly loads the scene a species lives in, copies a live creature out of it, gives the copy a fresh identity, drops it on solid ground near you, and unloads the scene again. That's the 1–6 second pause on a cold spawn, and it's why the result behaves perfectly — it's the same creature the game itself would have spawned, not an imitation.

The creature roster comes from DonorKit, which owns the table mapping each species to the scenes it can be found in — the harvest engine that fetches them, the expedition tier for region-only species, and the session template store SpawnKit's prewarm cache rides on: SpawnKit's templates live in the store's spawn kind, while all the spawn policy (normalization, the rig reject, the LRU cap) stays SpawnKit's. A third mod can even add a spawnable species without touching SpawnKit, via DonorKit.TemplateStore.RegisterSpecies / RegisterTemplate. spawnlist prints the roster. You can add or fix an entry without rebuilding anything by dropping a DonorScenes.txt into BepInEx/config/:

Hyena=Emercar_Dungeon5,ChersoneseDungeonsSmall
Alpha Tuanosaur=Hallowed_Dungeon3,HallowedMarshNewTerrain

Region-only creatures need an extra step. Open-world regions and towns are too big to load in the background — trying it crashes the game, so SpawnKit refuses to. Creatures that live only out in a region (Pearlbird, Torcrab, Coralhorn and friends) therefore can't be fetched the usual way; their rows are labelled (expedition-only) and a cold spawn fails with a clear message. To stock them, run an expedition: SpawnKit takes the whole party through a loading screen to the donor region and back (saving on each leg), and from then on that creature spawns like any other. Use spawnexpedition <species>, or the menu's expedition button.

Room-wide warm mirror (co-op)

The problem. A cold spawn is cheap on the machine that chose it and brutal on the one that didn't. When the host spawns a species a guest holds no body template for, that guest has to additively load a whole donor scene on its main thread to mirror the creature — measured in the field at 3.6 s (Obsidian Elemental), 12.1 s (Ghost) and 14.7 s (Elder Medyse), mid-fight, in a dungeon. Photon's 10 s disconnect timeout sits inside that range, which is why the reported symptom was a guest "constantly disconnecting during fights". The guest-side backstop (see docs/guest-mirror-harvest-testplan.md) can refuse such a spawn, but only the host can avoid choosing it — and for that the host has to know what every guest already holds.

The mechanism. Every peer publishes its own warm set. SpawnKit registers one NetKit replicated store, warm, on the sk channel with PeerOwned authority: each peer owns exactly one row, the receiver keys that row by the unforgeable sender actor, and every machine — host included — mirrors every other peer's row. The payload carries the peer's mintable species, its proven dead ends, and its remaining donor-harvest budget, so the host never wants forever against a guest that structurally cannot comply.

  • Publishes are change-latched on the encoded bytes (sk.warmset): a re-publish of an unchanged set sends nothing, so the mirror can be as trigger-happy about marking itself dirty as it likes.
  • A 30 s refresh heartbeats each row so a dropped message cannot leave a mirror stale forever, and the store flushes to a late joiner on its scene-ready edge — nobody has to ask.
  • Events (a template cached or evicted, a finished warm, scene-ready, room change) are latency; a 2 s verification poll is correctness, because the expedition cache has no change seam at all.
  • There is deliberately no sk.warmed confirm message. The row is the confirm: it lands exactly when the set actually grew. Two paths to the same fact with different arrival orders is how you get "the host thinks it's warm and the mirror says cold".
  • sk.want (master → one actor) is the only other new verb: "warm this species when it is safe, at the head of your queue." The guest still decides when that is — out of combat, no save pending.

The host gate. [Coop] RoomWarmMode decides how strictly a spawn is gated on the party rather than on this box:

Mode What the host does
Local ignores peers entirely — the pre-co-op behaviour
RoomDegraded (default) spawns anyway, names the cold actors in the log, and asks them to warm the species so the next one is instant
RoomStrict refuses the spawn (FailReason.SpeciesColdOnPeer, actors named)

RoomDegraded is the default because a road ambush that silently stops arming is a worse experience than one guest paying a donor load. RoomStrict is the setting for a party that would rather see fewer enemies than have anyone stall mid-fight.

Two verdicts are kept apart on purpose. ColdLocally means this machine can't mint it — not a peer's fault, and never reported as one. SpeciesColdOnPeer means the host could have minted it and a named guest could not; that is the only verdict the room gate owns, and the only one a sk.want can fix. Dev verbs escape per call with a trailing force token (spawn, spawnex), which sets SpawnOptions.IgnoreRoomWarm — deliberately not a config key, because a forgotten global would silently disable the gate for every consumer.

The fluke path. A miss is not fatal, it is a request. The host keeps a want book per (actor, species): send, then wait out [Coop] RoomWarmRequestTimeoutSeconds (30 s, doubling to RoomWarmRequestMaxTimeoutSeconds) before re-asking, up to RoomWarmRequestAttempts times, then give up once with a single [MIRROR] line. A guest that reports the species a dead end, or that has zero harvest budget left, is given up on immediately — that is a structural no, not a slow yes. RoomWarmRequestCap bounds how many species one RequestRoomWarm call may ask of one peer (3), and the caller's priority order goes to every peer, so the room-wide intersection converges instead of two guests warming disjoint halves.

Forgiven cold-unsafe. A guest can still refuse a spawn with sk.fail(cold-unsafe) after the room gate was satisfied — an eviction that lost a race, not a lie. The first such refusal for a uid is forgiven: the host logs [SKNET] cold-unsafe DESPITE room gate, sends sk.want, and keeps the creature so the guest's own detached acquire can finish. When the guest's set then grows, the host re-flushes the forgiven spawns to it ([SKNET] re-flushed N forgiven spawn(s)…); a pure ledger holds a ~60 s safety net, so a forgiven creature that is never mirrored despawns rather than lingering as a ghost, and a second refusal for the same uid despawns immediately. See SpawnNet.OnFail. That log line is the Phase B/C regression alarm — in a healthy RoomStrict session it should never appear.

Invariants worth knowing. - An unmodded or still-loading peer never vetoes. Only a peer that has actually published a warm set participates; anyone else is invisible to the gate, exactly as before. - Solo play is byte-identical in every mode. Zero participating peers ≡ local truth. - "The guest is warm for 4 of 13 species" is normal, not a bug. A guest warms what it has been asked for and what it has mirrored; the intersection grows over a session. - There is a quiet window right after a join. Until a fresh guest's row lands and the first sk.wants are answered, the room-wide intersection is small and RoomStrict will arm fewer ambushes. That is the gate working.

Seeing it. skwarmdump prints this machine's set, dead ends and remaining budget, then every peer's row — Unmodded (no compatible SpawnKit), HelloedNoRow (helloed, set not in yet), or Participating with its age, species and budget — then the room-wide intersection and the whole want book. spawnlist, the spawn menu and DangerousRoads' roadsroster share one glyph key: ● room-wide warm · ◐ warm here, cold on a peer · ○ cold here.

Wire version. These verbs ship under sk channel version 0.5.0, matched by exact ordinal comparison. A mixed-build room does not half-work: the handshake reports the peer as incompatible, says so loudly in the log, and co-op spawning stays off toward it. Update everyone together.

Warm-mirror settings

BepInEx/config/cobalt.spawnkit.cfg:

Setting Default What it does
[Coop] RoomWarmMode RoomDegraded Local / RoomDegraded / RoomStrict — how strictly a spawn is gated on the whole party being able to mint the species (see above).
[Coop] WarmSetPublishSeconds 1 Minimum seconds between two publishes of this machine's warm set; every dirty event coalesces into one. Raising it costs freshness, not correctness.
[Coop] RoomWarmRequestCap 3 Max species asked of ONE peer per RequestRoomWarm call. 0 or negative = uncapped.
[Coop] RoomWarmRequestTimeoutSeconds 30 How long the host waits for a guest to answer an sk.want before re-asking. Long on purpose — answering means running a donor load, deferred to a safe moment.
[Coop] RoomWarmRequestMaxTimeoutSeconds 120 Ceiling on the doubling backoff between retries. Values below the timeout are clamped up, never rejected.
[Coop] RoomWarmRequestAttempts 3 How many times the same sk.want is sent before the host stops asking for that (peer, species) this session. Minimum 1.
[Coop] GuestPrewarm true A guest may warm a species on its own initiative — the menu's Prewarm button and spawnprewarm — instead of being refused as host-only. The ask is queued and runs under the same deferral rules as a host's sk.want (never in combat, never while the loader/save is busy). false = the old UI: Prewarm greyed (host only). Spawn and Warm (trip) stay host-only regardless.
[Coop] GuestPrewarmBudget 4 Donor cycles a guest may spend per room on its own prewarm asks — a bucket separate from MirrorHarvestBudget, so the host's spawn choices and the player's own never compete. 0 = unlimited (the ceiling still applies).
[Coop] GuestDonorCycleCeiling 10 Hard per-session cap on donor cycles a guest spends across both buckets. Donor cycles are the LightProbesManager crash resource (~11–17 per process); the room buckets reset, this does not. A reached ceiling refuses every guest warm with session-ceiling and publishes budget=0 so the host stops asking. 0 = no ceiling. 
[Coop]
RoomWarmMode = RoomDegraded
WarmSetPublishSeconds = 1
RoomWarmRequestCap = 3
RoomWarmRequestTimeoutSeconds = 30
RoomWarmRequestMaxTimeoutSeconds = 120
RoomWarmRequestAttempts = 3
GuestPrewarm = true
GuestPrewarmBudget = 4
GuestDonorCycleCeiling = 10

Guest voluntary warm. A guest's Prewarm button (and spawnprewarm) is live when GuestPrewarm is on: the species is queued, not harvested on the spot, and the row reads (queued to warm when safe (in-combat)) / (warming now) until it lands. The menu's footer shows (guest warm N/M) — voluntary cycles spent against GuestPrewarmBudget. skwarmdump on the guest prints a local buckets: line (mirror a/b voluntary c/d session e/f) and the class-tagged queue (Ghost(host), Hyena(voluntary)). The budget= the host sees is min(mirror-left, ceiling-left) — the voluntary bucket is local-only, since the host's only use of that number is "may I send this peer an sk.want".

Built 2026-08-20 (mirror) / 2026-08-24 (guest voluntary warm), not live-verified. Rows GM10–GM28 in docs/guest-mirror-harvest-testplan.md are the live gates.

Settings

BepInEx/config/cobalt.spawnkit.cfg, created on first launch:

Setting Default What it does
[Spawner] Enabled true Master kill-switch. Off = no new spawns (cleanup still works).
[Spawner] AllowSpawnInRoom false Override the co-op safety gate: spawn in a room even when a peer doesn't have SpawnKit. Those peers see nothing (the spawn is an invisible ghost to them, and locks the host in unwinnable combat), so it's off by default. Solo play never consults this.
[Spawner] MaxActiveSpawns 8 Cap on live spawns at once (pending spawns count).
[Spawner] SpawnDistance 5 How far from you they appear, in meters.
[Spawner] MaxCachedTemplates 12 How many creature bodies stay in memory. Higher = more instant spawns, more RAM. 0 = unlimited.
[Spawner] DefaultCorpsePolicy Vanilla Vanilla leaves the corpse and its loot. NoBody deletes the corpse (and its loot) after death.
[Spawner] DefaultCorpseLingerSeconds 0 Seconds a NoBody corpse lingers (death-anim time) before it's removed.
[Spawner] ForceLootableEnabled true Re-enable a disabled loot component on a spawn so its corpse is lootable. Doesn't invent loot — a creature with no drops still drops nothing.
[Menu] EnableMenu true The in-game spawn menu.
[Menu] MenuKey Backslash Key that toggles the menu (rebindable).
[Expedition] EnableExpeditions true Allow fetching a region-only species via a real loading-screen round trip. Off = those rows only spawn if something already cached the body.
[Expedition] ConfirmMenuExpedition true Require a second click in the menu to launch an expedition (a stray click shouldn't teleport the party and write a save).
[Coop] EnableCoopSpawns true Replicate host spawns to guests running SpawnKit. Off = spawns refuse in a co-op room.
[Coop] DespawnOnMirrorFailure true If a guest can't mirror a spawn, despawn it everywhere (safer than leaving a ghost).
[Coop] MirrorQueueTimeoutSeconds 20 How long a guest holds a received spawn (waiting for its scene) before giving up.
[Coop] VerboseNet true Extra guest-side [MIRROR] mirror-queue logging (duplicate-drop / unknown-uid lines). The per-message co-op send/receive lines are NetKit's — those are governed by [Net] VerboseNet in NetKit's cfg.
[Coop] HeartbeatSeconds 30 Deprecated and ignored. The co-op heartbeat now rides NetKit's [Net] HeartbeatSeconds; this key is kept only so an existing value doesn't error. A non-default value logs a warning pointing at NetKit's cfg.

BepInEx has no config file-watcher, and SpawnKit registers no config-reload verb, so an edit to this file takes effect on the next launch. A few settings — the corpse policy and cached-body cap — apply to new spawns only.

Example configuration

BepInEx/config/cobalt.spawnkit.cfg — created on first launch. Excerpt:

[Spawner]
Enabled = true
MaxActiveSpawns = 8
SpawnDistance = 5

[Menu]
EnableMenu = true
MenuKey = Backslash

[Expedition]
EnableExpeditions = true
ConfirmMenuExpedition = true

[Coop]
EnableCoopSpawns = true

Dev commands run from BepInEx/config/SpawnKit_cmd.txt, and the species→scene table is config-overridable by dropping BepInEx/config/DonorScenes.txt (see How it works). The shared-settings overlay is config/shared/cobalt.spawnkit.cfg.overlay (see config/README.md).

Commands

Everything the menu does is also driven by writing a line into BepInEx/config/SpawnKit_cmd.txt — it runs on the next poll, even while the game is paused. Useful for scripting, or if a keybind conflicts. Unknown verb or help lists them all.

Verb What it does
spawn <species> [count] [force] Spawn 1 or more beside you. Names may contain spaces: spawn Armored Hyena 3. force ignores the room-wide warmth gate for this call.
spawnex <species> [dist=N] [life=N] [faction=Name] [owner=tag] [body=vanilla\|none] [linger=N] [keepquest] [force] One spawn with the full per-spawn option surface.
despawnall [kill] Remove every spawn. kill gives them a real death (animation + loot) instead of deleting them.
despawnowner <tag> [kill] Remove only spawns tagged with <tag>.
spawnlist / spawndump List spawnable creatures / show what's live right now.
spawnprewarm <species> / spawnprep <scene> Pay the body-fetch cost now so later spawns are instant.
spawnclearcache Drop cached bodies (frees memory; next spawn re-fetches).
spawnexpedition <species> [spawn] [force] Fetch a region-only species via a loading-screen round trip; spawn also spawns it on return.
expeditionreset Force a stuck expedition guard open (the fix for "the spawn menu stopped opening"). Doesn't teleport anyone.
spawnmenu Toggle the in-game menu regardless of MenuKey.
lootprobe Per-spawn corpse-loot diagnosis.
bonedump Skeleton/rig diagnosis for a spawned body (the "stretched to a vertical line" failure mode).
postrace <name\|uid:xxx> [seconds] [hz] Position trace on one live spawn: grounded/falling/agent/ragdoll/clip + what its collider overlaps, one line per sample (for "the enemy keeps launching into the sky"). postrace off stops it.
skwarmdump Warm-mirror census: this machine's warm set, every peer's row, the room-wide intersection and the want book (see Room-wide warm mirror).
skcoopdump Co-op state on this machine: handshakes, mirrored spawns, message counters. (More co-op dev verbs under help: skinject / skfail / skdrop / skresync / skgone / skstream / skfollow.)
selftest Sanity-check the install; look for [SELFTEST] … DONE in the log.

"My spawn just stands there" — reading aiLive=

Every [SPAWN] mint line and every spawndump row carries an aiLive= field: the one-glance answer to can this creature engage on its own?

aiLive= Meaning / what to do
Ticking Live. It can detect and attack by itself.
WorldPaused The world sim is paused — nothing detects or wanders, spawned or vanilla, even though every dev verb still answers normally. Run Beastwhispering's unstick fix, then re-check.
AiBehaviourDisabled The AI component is switched off — usually the far-distance cull. Get closer, or raise [AI] AiDisableDistance.
NotStartInitialized The body's start-up never finished, so detection is dead while wandering still looks normal. Try ghostdiag <name> fix.
DistanceCulled No player inside its enable distance. Close the gap.
NoAiGraph No usable AI at all — report it; this body should never have been spawned.

A related trap on the same line: charAIDisable=True does NOT mean the AI is disabled. It only reports that the distance-culling component exists, which is the healthy default for most creatures. Read aiLive=, never charAIDisable=.

To make a creature attack on command rather than waiting for it to notice you, use AggroKit's attack / forcetarget verbs — see AggroKit.

SpawnKit also registers ForgeKit's shared CommonVerbs pack on the same channel, so give, goto, teleport, settime, learnskill, scenedump and the rest are available here too.

Known limitations

  • Some creatures don't work. Roughly a quarter of the rows in the list can't be fetched — their body isn't in the scene the table expects, or they're region-only and not stocked yet. You get a clear message in the log rather than anything harmful.
  • Co-op is host-driven. With [Coop] EnableCoopSpawns=true, the host spawns and every guest running SpawnKit mirrors the creature as a real networked enemy — it moves, fights, dies and drops loot for everyone. Guests can't start spawns themselves (refused cleanly). If any player in the room doesn't have SpawnKit, in-room spawns refuse and the log names who, because to them the spawn would be an invisible ghost. [Spawner] AllowSpawnInRoom=true overrides that, knowingly; the whole co-op wire rides NetKit.
  • ⚠ Everyone in a co-op room needs the SAME SpawnKit build (0.5.0 on all boxes). 0.5.0 added the warm-mirror verbs (sk.warmset / sk.warmclr / sk.want) and the sk channel version is compared by exact ordinal match, so a 0.4.0 peer is reported incompatible and co-op spawning stays off toward it — loudly, not half-working. The 0.4.0 co-op wire changed shape when the spawn lifecycle moved onto NetKit's replicated-record store, and it is deliberately not backward compatible. Mixing 0.4.0 with an older build doesn't half-work — the handshake reports the peer as incompatible and co-op spawning stays off toward them, which is the intended outcome. Update everyone together and it's a non-event.
  • A rare visual glitch. Very occasionally, after a lot of spawning in one session, a patch of ground can go invisible (you can still walk on it) — changing zone and coming back repairs it.

Troubleshooting

Symptom What it means What to do
No spawnable species matches '<x>' Not in the table Check spawnlist; add a line to BepInEx/config/DonorScenes.txt
has NO additive donor — every candidate is an oversized region/town scene A region-only creature, not stocked yet Run spawnexpedition <species> (or the menu's expedition button)
First spawn of a creature pauses, later ones don't Normal — that's the body fetch Use spawnprewarm to pay it early
No mods load at all, no crash log Wrong Steam branch (IL2CPP instead of Mono) See Installing

For modders

SpawnKit is also a library. Reference it and declare the dependency:

[BepInDependency(SpawnKit.Plugin.GUID)]

Then spawning is one line:

SpawnHandle h = Spawner.Spawn("Hyena");

Everything else is optional — per-spawn customization rides a SpawnOptions, and the returned SpawnHandle is your window onto the creature's lifecycle:

Spawner.Spawn("Alpha Tuanosaur",
    new SpawnOptions
    {
        Faction = Character.Factions.Tuanosaurs, // null = the donor's own faction
        Distance = 12f,                          // ring-probe radius (clamped 1–50m)
        // Position = somewhereExact,            // skip the ring probe entirely
        LifetimeSeconds = 120f,                  // auto-despawn clock (null = forever)
        Corpse = Core.CorpsePolicy.NoBody,       // destroy the corpse after death (null = the
                                                 //   [Spawner] DefaultCorpsePolicy config;
                                                 //   NoBody takes the LOOT with it — see traps)
        CorpseLingerSeconds = 8f,                // death-anim time before the NoBody destroy
        OwnerTag = "mymod",                      // namespace your spawns (see DespawnAll)
        // StripQuestEvents = false,             // default true — leave it unless you KNOW
        ConsumerData = "objective:3",            // opaque string; reaches co-op guests (below)
        OnBeforeActivate = (go, ch) =>           // last touch before the creature wakes up
        {
            go.AddComponent<MyObjectiveMarker>();
        },
    },
    onReady: handle =>
    {
        if (!handle.IsAlive) { /* handle.FailReason says why */ return; }
        handle.OnDied += _ => DropReward();
        handle.OnDespawned += _ => CleanupMarker();
    });

The full surface (SpawnKit.Spawner, all static):

Call What it does
Spawn(species, options?, onReady?) Spawn ONE creature; returns a SpawnHandle immediately (Pending → Alive/Failed; sync refusals return already-Failed with a FailReason). One call = one creature — loop for more; a cold-species loop still costs one fetch (in-flight acquires dedup).
Despawn(handle, kill=false) Remove one spawn: kill = real damage pipeline (death anim + loot, → Died); silent = destroy (→ Despawned). Cancels a still-Pending handle.
DespawnAll(ownerTag=null, kill=false) Sweep by owner tag. null = EVERYTHING — that's the operator verb; mods should pass their own tag.
Prewarm(species, onDone?) / IsPrewarmed(species) Pay/check the body fetch off your hot path.
CanMintNow(species) True if a spawn can mint a body right now, from either cache (prewarm or expedition) — the question UI actually wants.
IsExpeditionOnly(species) / IsExpeditionCached(species) Whether a species can only be stocked by an expedition, and whether one already has.
Expedition(species, onDone?, force=false) Go fetch an expedition-only species (party round trip, saves on each leg). Host/offline only.
Active(ownerTag=null) Snapshot of tracked handles (Pending + Alive). Host-side — on a co-op guest this is empty (see below).
Replicas() Snapshot of the mirrored creatures on THIS machine — the guest-side counterpart of Active(). Empty on the host/solo.
OnMirrored Event: fires on a guest each time a mirrored creature finishes arriving.
SpeciesKeys() / ResolvedDonorName(species) The spawnable roster, and the real donor creature a species key resolves to (once revealed).

Two extension seams

OnBeforeActivate(GameObject, Character) runs on the freshly built creature before it wakes up — after SpawnKit has finished stamping its identity, and before the game's own initialization runs. That ordering is the whole point: anything the creature's own start-up reads (a marker component you want present from frame one, a loot-table edit, an AI tweak) has to be in place before activation, because by the time onReady fires it is already a frame too late. Keep it cheap, don't activate the object yourself, and note that a throwing hook is logged and skipped — it never aborts the spawn. Host-side only.

ConsumerData is an opaque string you attach to a spawn. In co-op, SpawnKit already mirrors your creature onto every guest for free — but until now the guest had no way to tell which of your creatures it was looking at, because delegates and object references cannot cross the network. ConsumerData can: whatever you put on it comes back on the guest, unchanged.

// On a guest — find your own mirrored creatures.
Spawner.OnMirrored += info =>
{
    if (info.ConsumerData == "objective:3") MarkObjectiveVisible(info.Uid);
};

foreach (ReplicaInfo r in Spawner.Replicas())
    Log.LogMessage($"{r.SpeciesKey} {r.Uid} state={r.State} data='{r.ConsumerData}'");

ReplicaInfo is plain read-only data (uid, species, state, view id, your string) — deliberately not the Character. Guests observe mirrored creatures; the host drives them. Keep the string short: it travels with the creature every time the spawn is synchronized. A peer running an older SpawnKit simply ignores it, and a spawn from an older peer reads back as "".

Trap table — read before shipping on this

Trap Rule
handle.Character can go Unity-null under you (scene unload, despawn) Check handle.IsAlive before every use; never cache the Character across scene loads.
Spawns are ephemeral by design Scene unload = OnDespawned, and saves skip SK_ UIDs both directions. Don't build persistence on top.
A cold species blocks ~1–6s before onReady Prewarm on your init path if the spawn must feel instant.
MaxActiveSpawns is global across all consumers (pending spawns count too) Tag your spawns (OwnerTag) and never call DespawnAll(null) from a mod — you'd sweep other mods' spawns.
A consumer's own cap can bind long before SpawnKit's, and users will blame SpawnKit If you enforce a private cap, say so in that key's description and log the block naming BOTH keys and BOTH files — otherwise "it stops at 6 whatever I set MaxActiveSpawns to" is the bug report you get (it is the one we got: DangerousRoads' [Wave] MaxOwnActive, 2026-08-02).
Callbacks run on the main thread inside the watch tick Keep them cheap. A throwing callback is isolated (swallowed + logged) — it won't break SpawnKit, but you won't get a second chance either.
Co-op clients always get Failed/NotMaster — guests never initiate Design your feature so only the host drives spawning. Host-side in-room spawns work when every peer handshakes; otherwise the refusal names the unmodded peer.
An unmodded guest in the room blocks in-room spawns (PeersNotReady) That's the feature: a spawn would be an invisible ghost to them. AllowSpawnInRoom=true overrides, knowingly.
A guest's first mirror of a species runs its own ~1s donor harvest Prewarm on both machines if it matters.
Late-join / scene-return flush covers Alive spawns only A guest joining never sees pre-existing corpses; a NoBody corpse removal can destroy a loot container a guest has open (same as a scene unload mid-loot — vanilla tolerates it).
StripQuestEvents = false on a quest-flagged creature fires real quest events on death The default (true) exists because live donors really do carry quest triggers — leaving it on is what keeps spawns from mutating quest state.
CorpsePolicy.NoBody destroys the loot bag with the body The corpse GameObject IS the loot container — never combine NoBody with a drop-loot expectation.
Ring geometry (step angles, elevation band, navmesh snap) is not configurable By design. If you need exact placement, pass SpawnOptions.Position and own the spot yourself.
The species roster and creature supply are DonorKit's, not SpawnKit's An expedition-only species fails cold spawns until an expedition stocks it.
Active() is empty on a co-op guest It is the host's registry. A guest sees mirrored creatures through Replicas() / OnMirrored, which carry ReplicaInfo, not handles.
OnBeforeActivate runs before the creature is initialized Half the Character is not set up yet. Add components and edit data there; do anything that needs a live creature in onReady instead.
ConsumerData is not a channel It is a fixed label attached to one spawn, sent when that spawn is synchronized. It never updates in place — if the value must change over time, replicate that yourself.

See also