chain-reaction

Chain Reactor

What it is

A unique artifact that rewards killing enemies. Every kill triggers a burst of speed and a short window of invulnerability, letting the ship plough through follow-up waves before the boost fades. The proc is gated by a cooldown, so it cannot fire on every kill back-to-back.

Identity

Field	Value
Display name	Chain Reactor
Category	Unique
Icon	💨
Primary color	ff8800
Secondary color	cc5500
Bright/highlight color	ffbb44
Damage tag	None (type-agnostic)

Per-tier values

Tiers are indexed by rarity. The four authored tiers cover uncommon through legendary; the runtime prepends a fifth “common” tier that reuses the uncommon row’s values and only adds a smaller flat passive bonus.

Rarity	Speed boost (multiplier added to max speed)	Effect duration (seconds)
Common	+60%	1.5
Uncommon	+60%	1.5
Rare	+80%	2.0
Epic	+105%	2.5
Legendary	+140%	3.0

Effect

Trigger: any enemy kill signal.

Cooldown between procs: 4.0 seconds.

When the cooldown is clear and a kill fires, the artifact runs the following actions in order:

Action	Effect
Max-speed modifier	Adds the tiered speed boost to max speed as a percent modifier, lasting for the tiered duration.
Grant invulnerability	The ship cannot take damage for the same tiered duration.
Visual burst	Plays a burst-and-ring VFX in the artifact’s bright color (26 particles, scale 5.5, lifetime 0.40 s).
Artifact flash	Flashes the artifact’s HUD icon to signal the proc.
Banner	Shows the artifact’s banner the first time it procs in a run.

The speed and invulnerability share the same duration, so they expire together.

Stacking rules

Rule	Behavior
Max stacks	1
Stacking mode	Refresh — a fresh proc replaces the existing speed buff, resetting its remaining duration to the full tiered value.
Modifier source	artifact:chain_reaction (used to find and refresh the existing modifier rather than adding a second copy).
Cooldown gating	The 4.0 s cooldown is independent of duration. With longer durations at higher tiers, the buff can be permanently maintained against dense enemy spawns once the cooldown is shorter than the effect duration.
Invulnerability stacking	Each proc grants invulnerability for the tiered duration; subsequent procs effectively refresh the window via the same trigger.

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Summary: Chain Reactor is a unique kill-triggered artifact granting a stacking-refresh max-speed percent buff plus matched invulnerability, on a 4.0 s cooldown. Speed boost scales 60% → 140% and duration scales 1.5 s → 3.0 s across common/uncommon → legendary. Common reuses uncommon’s values per the shared-tier convention.

EXTRACT-CANDIDATE flags:

• The “5th common tier reuses uncommon values and differentiates via flat passive bonus” rule is shared across all artifacts and belongs on the artifacts roll-up page, not duplicated per entity.
• The FLAT_BONUS_PCT_BY_TIER table (10 → 50 across common → legendary) referenced in _types.ts is engine-wide and should live on the artifacts overview / authoring guide.
• The stacking: 'refresh' / maxStacks modifier semantics are a generic effect-engine concept; canonical definition belongs on a combat or effect-engine page.
• The grant_invuln, modify_stat, vfx, flash_artifact action types are shared primitives across many artifacts — canonical reference belongs on the artifact authoring guide.
• Color-palette schema (primary / secondary / bright) is shared across all artifacts and belongs on the roll-up, with per-entity pages only listing the values.