Slipstream
What it is
Slipstream is a stat-category artifact that procs on a repeating internal timer. Each proc grants the ship two simultaneous timed buffs — full immunity to enemy projectiles and a large flat boost to weapon damage — for a short window. Within the timer-driven defensive-burst family it is the only artifact that combines a hard projectile-immunity window with an offensive damage swing in the same proc, making it both a survival cooldown and a damage cooldown sharing a clock.
Identity
| Field | Value |
|---|---|
| Display name | Slipstream |
| Category | stat |
| Icon | checkered flag |
| Damage tag | none (type-agnostic) |
| Trigger type | timer |
| Trigger repeats | yes |
| Banner on proc | yes |
| Proc audio cue | none defined |
| Primary color | 00ffcc |
| Secondary color | 00cc99 |
| Bright color | 66ffdd |
The trigger is a self-repeating timer keyed off the tier’s interval value. There is no kill-streak condition, no damage-type gate, and no other entry condition beyond the timer firing.
Per-tier values
Tiers indexed 0 → 3 map to uncommon → rare → epic → legendary. A fifth common tier is prepended at runtime via the engine’s flat-bonus layer and shares the uncommon values record.
| Tier | Rarity | Proc interval (s) | Buff duration (s) | Damage boost (%) |
|---|---|---|---|---|
| 0 | Uncommon | 10 | 3 | 50 |
| 1 | Rare | 9 | 3 | 90 |
| 2 | Epic | 8 | 4 | 140 |
| 3 | Legendary | 6 | 4 | 200 |
The proc interval shortens, the buff duration lengthens, and the damage boost scales with tier. At legendary the buff is active for 4 out of every 6 seconds, i.e. roughly two-thirds of the run uptime.
Effect
On every timer tick, the artifact fires two stat-modifier actions in the same frame plus a VFX burst and a flash on the artifact icon.
| Element | Value |
|---|---|
| Stat 1 modified | projectile immunity (internal flag) |
| Stat 1 mode | flat additive, value 1 |
| Stat 1 source tag | artifact:speed_demon:imm |
| Stat 2 modified | weapon damage (percent) |
| Stat 2 mode | flat additive percentage |
| Stat 2 source tag | artifact:speed_demon:dmg |
| Buff window | tier-defined buff duration |
| VFX type | burst-and-ring |
| VFX particle count | 26 |
| VFX scale | 5.5 |
| VFX lifetime (s) | 0.40 |
| VFX color | 66ffdd |
The projectile-immunity buff sets an internal ship flag for the buff duration; while the flag is set, enemy projectiles do not damage the ship. The damage buff is applied to the ship’s weapon-damage percentage stat as a flat additive percentage for the same buff duration. Both buffs share the same duration, the same source artifact, and the same start frame, but are tracked as two independent sources on the stat layer.
Stacking rules
| Rule | Value |
|---|---|
| Stacking mode (both buffs) | refresh |
| Max stacks (both buffs) | 1 |
Neither buff can accumulate. A second proc landing while the first window is still active resets the remaining duration on both buffs to the full tier-defined window without adding a second stack. Because both buffs share a single source artifact and a single trigger, they always start and end on the same frame.
When the proc interval is greater than the buff duration (tiers 0 and 1 — 10/3 and 9/3) the buffs lapse between procs and the ship is exposed during the gap. When the proc interval is less than or equal to the buff duration plus one engine tick (tier 3 — 6/4) the buffs effectively chain with only a brief gap. Tier 2 (8/4) sits between these regimes.
Slipstream does not share its trigger source with any other artifact; it has its own dedicated timer keyed off the artifact’s own interval. Other timer-trigger artifacts run on their own independent timers. Tier upgrades replace the per-tier values record wholesale. Tier is set at run start by meta-progression and does not change mid-run.
EXTRACT-CANDIDATE flags
- Timer trigger primitive. The
trigger: { type: 'timer', timerDuration: '$interval', timerRepeat: true }shape is a generic effect-engine primitive used by any artifact with a self-clocked proc. Threshold-binding via the$intervaltoken and the repeat semantics are engine-side and belong on aconcepts/effect-engine-triggers.mdpage rather than repeated per artifact. - Refresh stacking with max stacks = 1. Recurring buff-stacking mode across the stat-burst artifact family. Same flag as Frenzy / Aegis / Bloodlust / Salvager. Candidate concept page:
concepts/buff-stacking-modes.md. - Projectile immunity as an internal stat. The
_projectileImmuneflag is treated as a stat modified by the samemodify_stataction used for percentage stats. The underscore-prefixed stat namespace, the integer-flag semantics, and the interaction with the enemy-projectile damage path are engine-side and belong on aconcepts/projectile-immunity.mdor combat-pipeline page. - Multi-action proc with shared duration. Two
modify_statactions sharing one$durationtoken but distinct source tags is a reusable pattern for any artifact that buffs multiple stats together. Candidate concept page or roll-up section: paired buffs with independent stat-layer tracking. - Common-tier flat-bonus layer. The runtime adds a 5th common tier that shares the uncommon values record and differentiates only through a per-artifact flat-bonus field. Slipstream declares no
flatBonus, so common-tier behavior depends on engine defaults. Document once on the artifacts roll-up. - Weapon-damage stat composition. How the
weaponDamagePctship stat composes with other sources, base weapon damage, per-weapon overrides, and damage tags is not specified in the artifact file and belongs on a combat / weapon-pipeline page. - Banner, flash, and VFX actions.
showBanner: true,flash_artifact, and theburst_and_ringVFX recipe are shared UI/VFX primitives across many artifacts; their exact behavior is engine-side and should live on the artifacts roll-up or a VFX-primitives page. - Uptime ratio as a design lever. The (duration / interval) ratio progression across tiers (3/10 → 3/9 → 4/8 → 4/6) is a deliberate design curve and is a candidate for the artifacts roll-up’s tier-scaling discussion, not a per-entity prose paragraph.