Test Subject #C8 is a boss in Slay the Spire 2. Here is what she or he does, the moves to expect, and the order that actually wins.
A three-phase boss that revives twice with increasing HP (100 → 200 → 300) and different modifiers each phase. Adapts to punish your strategy.
The fight at a glance
| Act | Act 3 |
| Location | Glory |
| Difficulty | Very Hard |
| HP | 100 |
| Key mechanic | Adaptable (3 Phases) |
The rotation
Phase 1 (100 HP): Attacks while gaining Strength from your Skills. Phase 2 (200 HP): Attacks while punishing unblocked damage with Wounds. Phase 3 (300 HP): Attacks with Intangible on alternating turns.
Moves
| Move | What it does |
|---|---|
| Standard Attack | Basic attack dealing ~18 damage, scaling with Strength. |
| Heavy Attack | Strong attack dealing ~30 damage. |
| Enrage (Phase 1) | Passive: gains 2 Strength every time you play a Skill card. |
| Painful Stabs (Phase 2) | Passive: every point of unblocked damage inserts a Wound into your discard pile. |
| Intangible (Phase 3) | On alternating turns, all incoming damage is reduced to 1 per hit. |
How to beat Test Subject #C8
- Phase 1: Minimize Skill card usage — focus on Attacks and Powers to avoid feeding it Strength. Phase 2: Block everything — unblocked damage fills your deck with Wounds. Phase 3: Use multi-hit attacks on non-Intangible turns and focus defense on Intangible turns. Total HP to deal: 600 across all three phases. This is a marathon — conserve resources.
- Phase 1: Attacks and Powers don’t trigger Enrage — save Skills for when you must Block
- Phase 2: Perfect Block is essential — every unblocked hit adds Wounds to your deck
- Phase 3: Multi-hit attacks are useless during Intangible — time your burst for off-turns
- Total 600 HP across all phases — this is an endurance fight
Where to go next
The boss table lists every boss with HP and key mechanic. The deckbuilding basics page covers building for fights like this one.