Slay the Spire 2 The Test Subject boss guide

Act 3 of Slay the Spire 2 has multiple menacing and vexing enemies and bosses, and many players believe that one of the most annoying to deal with is the Test Subject. The Test Subject is a tanky boss with three phases. Each phase will test how well you can manage your energy and cards.

So if you’re here to find out exactly how to deal with it, you’re in the right place. Read on to learn how Slay the Spire 2’s Test Subject works and how to defeat it.

How to Defeat the Slay The Spire 2 The Test Subject Boss

The Test Subject boss has three phases. After depleting its large HP pool, it will be stunned, then move on to the next stage, reviving itself after a turn.

First Phase (100 HP)

During the first phase, avoid using Skill cards at all costs! At the very least, try not to stack too many Skill cards unless you can tank the upcoming attacks.

The Test Subject will have the Enrage status.

• Enrage: Whenever you play a skill, gains 2 strength.

While it can be tempting to block its attacks or use skills to enhance your deck, try to limit their use. Playing a Skill card increases this boss’s strength, allowing it to deal more damage. For this phase, the best approach is to deal as much damage as possible and tank its attacks for now.

After defeating it, it will collapse briefly, unable to attack. It will then heal and revive for phase two.

Second Phase (200 HP)

The boss now revives with another head, doubling its original HP to 200. It’s much tankier now, but this stage is at least easier if you have Block cards.

The second phase removes the Enrage status, but it is replaced by the Painful Stabs status.

• Painful Stabs: Shuffle 1 Wound into your Discard Pile each time you take unblocked attack damage.
  • Wound: Unplayable card.

The boss will continue dealing damage turn after turn, so, as usual, try to block whenever possible. Using Block cards not only prevents damage but also stops Wound cards from being added to your deck. Fortunately, Wound cards don’t drain health or resources, but they are unplayable and clutter your hand. If too many accumulate, you could end up with a hand full of useless cards.

Overall, this phase requires a balance between dealing damage and managing your hand with Block cards.

Third Phase (300 HP)

The Test Subject boss revives once again with a third head, increasing its HP to 300. This is its final phase, phew. However, it won’t be easy, as its damage increases each turn, and it can become intangible.

• Nemesis: At the end of every other turn, gains Intangible 1.
  • Intangible: Reduce all damage taken and HP loss to 1. Lasts for 1 turn.

Every other turn, the boss will become intangible, making high burst attack useless during this turn.

Also, note that during its first and second turns, it will deal damage. On the third turn, it casts the Burning Growl skill, adding three Burn cards to your Discard Pile. This cycle then repeats.

• Burn: Unplayable. At the end of your turn, if this is in your hand, take 2 damage.

With this all combined, you better be patient. This is gonna be a long fight, trust me.

To handle this boss, make sure to follow these tips:

• Be mindful of the Intangible status. Use these turns to focus on blocking attacks or playing Skill and Power cards that improve your deck.
• Outside of Intangible turns, prioritize blocking, mitigating, or reducing its attacks while chipping away at its health.
• Make sure to block Burn damage as well, and save burst damage for its normal turns.

Check out more Slay the Spire 2 guides!

Slay the Spire 2 Status Cards – How they work