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Fossil Mound

Based on game build 714014 | Last updated: 2026-03-05

Overview​

The fossil_mound prefab represents a recoverable structure built from fossil fragments. It functions as a multi-stage repairable and tradable entity: players must first hammer it to reduce its size (revealing the fossil), then repair it using Fossil material, and finally trade it with a Shadow Heart during nighttime—subject to location-based constraints—to respawn a Stalker variant (forest, cave, or atrium). It leverages several core components: workable, repairable, lootdropper, trader, and inspectable, and integrates with areaaware and entitytracker for context-aware trading logic.

Usage example​

local inst = SpawnPrefab("fossil_stalker")
-- Defaults to moundsize=1, form=1 (correct). To set up for Stalker revival:
inst.moundsize = 8
inst.form = 2  -- Example of a "wrong" form for humorous Stalker
inst.components.trader:Enable()  -- Required for trading

Dependencies & tags​

Components used:
inspectable, lootdropper, workable, repairable, trader, areaaware, entitytracker, sanity
Tags: Adds structure to the instance.

Properties​

PropertyTypeDefault ValueDescription
moundsizenumber1Current size of the mound (1 to MAX_MOUND_SIZE = 8). Controls repair progress and loot count.
formnumber1Stalker form variant: 1 (correct/normal), 2 (funny), 3 (funny). Set when mound reaches MOUND_WRONG_START_SIZE (5).

Main functions​

UpdateFossileMound(inst, size, checkforwrong)​

  • Description: Updates the visual state, workable progress, and trading state based on moundsize and form. Also adjusts animation and enables/disables trading when full size is reached.
  • Parameters:
    inst (Entity) – the fossil mound instance.
    size (number) – the new mound size (clamped to [1, MAX_MOUND_SIZE]).
    checkforwrong (boolean) – if true, may randomize form when size crosses MOUND_WRONG_START_SIZE (5).
  • Returns: Nothing.

ItemTradeTest(inst, item, giver)​

  • Description: Validates whether the current trade conditions for reviving a Stalker are met. Enforces checks for Shadow Heart item, nighttime, location (Atrium-specific constraints), and correct Stalker form.
  • Parameters:
    inst (Entity) – the fossil mound instance.
    item (Entity or nil) – the offered item (must be "shadowheart").
    giver (Entity or nil) – the trader entity (must have areaaware component).
  • Returns:
    true if trade is allowed, else false, "REASON" (e.g., "WRONGSHADOWFORM", "CANTSHADOWREVIVE").

OnAccept(inst, giver, item)​

  • Description: Executes the Stalker revival logic: spawns the appropriate Stalker type, positions it over the mound, triggers resurrection state, and penalizes sanity.
  • Parameters:
    inst (Entity) – the fossil mound instance (removed during execution).
    giver (Entity) – the player performing the trade.
    item (Entity) – the Shadow Heart (consumed).
  • Returns: Nothing.

onworked(inst)​

  • Description: Handles hammering: spawns collapse FX, drops loot based on current moundsize, and destroys the mound.
  • Parameters:
    inst (Entity) – the fossil mound instance.
  • Returns: Nothing.

onrepaired(inst)​

  • Description: Increments mound size and updates visual state after repair. Plays repair sound.
  • Parameters:
    inst (Entity) – the fossil mound instance.
  • Returns: Nothing.

getstatus(inst)​

  • Description: Returns display status for scrapbook/inspect UI: "COMPLETE" if full size and correct form, "FUNNY" if full size but wrong form, nil otherwise.
  • Parameters:
    inst (Entity) – the fossil mound instance.
  • Returns: string? – "COMPLETE", "FUNNY", or nil.

onsave(inst, data)​

  • Description: Serializes moundsize and form if >1, for save compatibility.
  • Parameters:
    inst (Entity) – the fossil mound instance.
    data (table) – the save data table.
  • Returns: Nothing.

onload(inst, data)​

  • Description: Deserializes saved state, including backward compatibility for data.wrong.
  • Parameters:
    inst (Entity) – the fossil mound instance.
    data (table?) – saved data (may be nil).
  • Returns: Nothing.

Events & listeners​

  • Listens to:
    inst.OnSave → calls onsave(inst, data)
    inst.OnLoad → calls onload(inst, data)
  • Pushes:
    Via inst.components.lootdropper:DropLoot(...): entity_droploot
    Via inst.components.sanity:DoDelta(...): sanitydelta, goinsane/gosane, etc.
    Via inst:Remove(): onremove
    (No direct ListenForEvent calls are present.)