Sub-Projectile Types

Legendary weapons spawn secondary bullets and AoE bursts that aren’t in the player weapon registry. They live inside bullets.ts (src/starship-survivors/engine/weapons/bullets.ts) as world.playerBullets.push({...}) calls fired from a parent behavior’s update / onDeath / onHit hook, or as delayed-detonation bursts scheduled through the spawnDelayedAoE / spawnFlameZone primitives in engine/effects/custom-handlers.ts. Each sub-projectile carries an arch: tag (rendered as that archetype) plus a _behaviors: [...] list that tells the bullet runner which handlers to drive it with. Damage credit still flows back to the parent weaponId for telemetry.

The pool is capped: every spawn site is guarded by if (world.playerBullets.length < 100) to keep the bullet array bounded. Drops past 100 are silently lost.

Bullet-pushed sub-projectiles (carry arch: + _behaviors:)

These are real Bullet records with their own lifetime, position, velocity, and damage. They flow through the standard collision resolver and renderer.

arch tag	Spawned by	Parent legendary	What it does
plasma_fire_zone	plasma_mortar_land.onDeath (bullets.ts:2688)	Plasma Mortar (lgd_arc_flame)	Stationary radius zone, rad: 0, lives 3 s, ticks energy damage 4×/sec to any enemy in _zoneRadius (= 80 % of the shell’s blast radius). Per-tick dmg = ceil(parent.dmg × 0.10). Runs plasma_fire_zone behavior.
plasma_droplet	plasma_mortar_land.onDeath (bullets.ts:2747)	Plasma Mortar (lgd_arc_flame)	Three small cyan plasma droplets thrown radially at 280 px/s within a 60° spread from impact. Lifetime 0.3 s, rad: 25, first-hit collision, ~20 % of main damage. Runs plasma_arc behavior for visuals.
fire_patch	carpet_bomber.update per bomb drop (bullets.ts:2913)	Carpet Bomber (lgd_napalm_mortar)	Persistent ground fire patch dropped at every bomb landing site. Lives 2.5 s, ticks 5×/sec at _zoneRadius = 70 % of bomb blast radius. Per-tick dmg = ceil(bombDmg × 0.06). Runs fire_patch_zone behavior.
emp_ring	empWave.onDeath (bullets.ts:790)	(Non-legendary EMP weapons — listed for completeness)	Expanding ring AoE, lives 2 s, growing to _empMaxRad = parent.blastRadius, deals 80 % of parent damage. Not currently used by any legendary; the slot lives in the same registry path.
sniper	burst_fire.update per sub-shot (bullets.ts:746)	(Burst-fire base weapons)	Per-burst hitscan beam-trace bullet, lifetime 0.06 s, pierceCount: 999, _collisionMode: 'beam_trace'. The Mega Bullet legendary uses mega_bullet_trail instead and does not invoke burst_fire, so this arch is base-weapon only.
nova_ring	periodicRing.update (bullets.ts:114)	(Periodic-ring archetype)	Stationary ring, no damage, 0.25 s life, 3× the parent’s radius. Used by non-legendary periodic-pulse weapons.

The two zone-archetype bullets (plasma_fire_zone and fire_patch) are special: they have vx/vy = 0, rad: 0 (so the bullet-vs-enemy radius check never trips), and apply damage themselves inside their update handler via enemyGrid.query + damageEnemy. They are sub-projectiles only in the technical sense — really they are persistent damage zones riding the bullet pool.

Coordinator bullets and their virtual sub-projectiles

Some legendaries spawn one coordinator bullet that internally tracks many virtual “stars” or “stages” without each one being a real Bullet push. These don’t use arch: for the children — the parent owns the array.

• Star Halo (lgd_railstorm, orbit_ring behavior, bullets.ts:1802). The cast spawns a single coordinator bullet. Inside b._ringStarsList[] are 5–30 plain JS objects (one per “star”), each with its own {x, y, slotAngle, phase, contactCooldowns}. The coordinator drives all of them through stream → spin → burst_out → explode phases. Per-star explosion damage uses b._ringStarDmg (= spec.damage). Spin-phase sweep damage = 25 % of that, with per-star × per-enemy cooldown of one revolution.
• Railstorm (lgd_plasma_launcher, beam_decay behavior, bullets.ts:2069). The beam bullet stores _bdExplosionCount (6–14 by level via beamDecayExplosions) and schedules them as raw AoeExplosion.spawn + per-enemy damage loops over a 2 s decay window. No sub-bullets are pushed — each cascade is a position + radius + damage triplet evaluated inline.
• Hellrain (lgd_blackhole_cluster, artillery_rain behavior, bullets.ts:2182). The bomb itself is one bullet with two phases (telegraph → fall). The aoe_finish damage on landing comes from the standard aoe_finish behavior on the same bullet — not a new sub-projectile.
• Carpet Bomber (lgd_napalm_mortar, carpet_bomber behavior, bullets.ts:2823). The bomber is the coordinator. Each bomb drop applies AoE damage inline (no sub-bullet for the explosion itself), then pushes one fire_patch zone bullet (above) and one spawnFlameZone patch for the lingering-flames artifact stack.

Delayed AoE “echoes” (not bullets at all)

Several legendaries layer in a thematic “echo” — a small delayed burst that detonates after the main effect. These are pushed into a private _delayedAoEs[] array in engine/effects/custom-handlers.ts via spawnDelayedAoE(x, y, radius, damage, delay, c1, c2) and are ticked by tickDelayedAoEs(dt). They have no projectile body, no collision, no arch. On detonation they paint an AoeExplosion + impact ring and damage every enemy in radius once with distance falloff. The pool is hard-capped at DELAYED_AOE_MAX (oldest shifts out).

Echo name	Parent legendary	Where spawned	Pattern
Cluster Bomblet	Hellrain (lgd_blackhole_cluster)	artillery_rain.update impact frame (bullets.ts:2265)	One delayed AoE at the landing site after 0.4 s. Radius = 50 % of bomb blast, damage = 30 % of primary AoE damage.
Sparkle Wake	Star Halo (lgd_railstorm)	orbit_ring.update explode phase (bullets.ts:2040–2041)	Two tiny 15 px pulses per exploding star, at +0.20 s and +0.40 s. Per-pulse dmg = ceil(starDmg × 0.04).
Lingering Scar	Railstorm (lgd_plasma_launcher)	beam_decay.onDeath (bullets.ts:2155)	Six sample points along the beam path, each fires twice (at +0.05 s and +0.25 s). Radius = max(20, beamWidth × 0.35). Per-pulse dmg = cascade damage × 0.08.
Bomb Pyre	Carpet Bomber (lgd_napalm_mortar)	carpet_bomber.update per bomb drop (bullets.ts:2910)	Calls spawnFlameZone(landX, landY, 50, dmg × 0.20, 0.8) — a global-pool flame zone rather than a delayed AoE, but conceptually the same “echo” slot. Stacks with the lingering_flames artifact.
Slipstream Wake	Mega Bullet (lgd_autocannon)	mega_bullet_trail.onDeath (bullets.ts:2283)	Implemented inline (no helper call) — does its own 40 × 12 px oval damage check behind the slug at expiry, 25 % of slug damage. Listed here because it occupies the same “thematic echo” design slot.

Legendary → sub-projectile coverage

Legendary	Real sub-bullets	Virtual coordinator children	Delayed-AoE / flame-zone echoes
Mega Bullet (lgd_autocannon)	—	—	Slipstream Wake (inline oval)
Hellrain (lgd_blackhole_cluster)	—	—	Cluster Bomblet
Star Halo (lgd_railstorm)	—	5–30 stars in _ringStarsList	Sparkle Wake × 2 per star
Phoenix (lgd_inferno)	—	phoenix_pulse ring is a single coordinator	—
4-Way Burst (lgd_flak_rifle)	—	Hitscan only (quad_burst dispatcher)	—
Wave Gun (lgd_railslug)	—	—	—
Trailblazer (lgd_incendiary_rifle)	— (flame patches handled by the fire_trail weapon system, not as sub-bullets)	—	—
Railstorm (lgd_plasma_launcher)	—	6–14 cascade explosions inline	Lingering Scar × 12
Carpet Bomber (lgd_napalm_mortar)	fire_patch × 6–18 (one per bomb)	6–18 bombs (shellCount)	Bomb Pyre × N (one per bomb, via spawnFlameZone)
Plasma Mortar (lgd_arc_flame)	plasma_fire_zone × 1–3, plasma_droplet × 3 (per shell)	1–3 shells (shellCount)	—

Why not just register them as weapons?

These archetypes never appear in the player-facing weapon registry because they:

• have no acquire/fire pipeline (they don’t pick targets or schedule next-shot timers — the parent does)
• have no level-up entry (their stats are derived from the parent’s dmg, blastRadius, etc., at spawn time)
• have lifetimes counted in fractions of a second, designed as cleanup VFX-with-damage rather than independent weapons
• collide using the same _collisionMode + _canHitDestructibles flags as a regular bullet, so they piggyback on the resolver instead of adding a new path

Bullet pool / archetype catalog details live in bullet-archetypes and bullet-pool-recycle. Zone-tick mechanics are detailed in plasma-mortar-zones, carpet-bomber-zones, and flame-zones.