Fossil Spike

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

Overview

fossil_spike is a seasonal ground-based combat entity that erupts from the ground, performs area-of-effect actions (damaging, destroying, or tossing entities), then deactivates and disappears after a fixed duration. It is used in high-stakes combat scenarios (e.g., seasonal bosses) and works with the combat, workable, pickable, health, mine, and inventoryitem components. Two prefabs are defined: fossilspike (the primary erupting spike) and fossilspike_base (the static base visual).

Usage example

-- The fossil_spike prefab is automatically instantiated during seasonal events like the Boss Battle.
-- To manually trigger it (e.g., in a mod), use:
local spike = SpawnPrefab("fossilspike")
spike.Transform:SetPosition(x, y, z)

-- To programmatically restart or kill the spike:
spike.RestartSpike(delay, duration, variation)  -- delay: optional delay before next spike
spike.KillSpike()                               -- immediately kill and deactivate

Dependencies & tags

Components used: combat Tags: Adds notarget, groundspike, fossilspike (to main entity); adds FX, NOCLICK (to base entity).

Properties

No public properties are defined. The component exposes a RestartSpike and KillSpike function on the instance for runtime control.

Main functions

StartSpike(inst, duration, variation)

• Description: Initiates the active phase of the spike: sets up a delayed self-destruction timer, plays the eruption animation, spawns the base FX, emits sound, and executes a single DoDamage call. Typically called by RestartSpike or the initial constructor task.
• Parameters:
  • inst (Entity) — the fossil spike instance.
  • duration (number) — time in seconds before the spike is automatically killed.
  • variation (number) — specifies which animation variant to use (1–7).
• Returns: Nothing.
• Error states: None.

RestartSpike(inst, delay, duration, variation)

• Description: Cancels any existing scheduled KillSpike task and schedules a new StartSpike call after the given delay. Handles rounding of variation to valid range 1..NUM_VARIATIONS.
• Parameters:
  • inst (Entity) — the fossil spike instance.
  • delay (number or nil) — delay before restarting; if nil, restarts immediately (0 seconds).
  • duration (number) — duration of the next active phase.
  • variation (number or nil) — desired animation variation. If nil, a random variation is selected.
• Returns: Nothing.
• Error states: Does nothing if inst.task is nil.

KillSpike(inst)

• Description: Deactivates and begins removal of the spike. Plays a post-destruction base animation (base_pstN), schedules final removal, and prevents multiple kills via the killed flag.
• Parameters: inst (Entity) — the fossil spike instance.
• Returns: Nothing.
• Error states: No-op if already killed (inst.killed == true) or basefx is invalid.

DoDamage(inst)

• Description: Performs area-of-effect logic within a small radius. Interacts with nearby entities based on component presence and tags:
  • Destroys workable objects (e.g., campfires, rabbit holes) if valid.
  • Picks pickable objects unless they have the intense tag.
  • Kills or attacks valid combat targets depending on locomotor and epic tags.
  • Tosses inventory items and deactivates mines.
• Parameters: inst (Entity) — the fossil spike instance.
• Returns: Nothing.
• Error states: Skips invalid or dead targets.

SpikeLaunch(inst, launcher, basespeed, startheight, startradius)

• Description: Applies physics velocity to an entity (e.g., an item) to "launch" it away from the spike's center in a random arc. Used to toss item loot.
• Parameters:
  • inst (Entity) — the entity to launch (typically an item).
  • launcher (Entity) — the spike that is launching the item (used as origin).
  • basespeed (number) — base horizontal speed.
  • startheight (number) — vertical start height.
  • startradius (number) — max radial offset from origin.
• Returns: Nothing.

Events & listeners

• Listens to: animover — triggers ChangeToObstacle to convert the spike from an active projectile to a static obstacle after animation completes.
• Pushes: None directly, but relies on external events like picked, destroyed, and death triggered by associated component methods.