Waterfall Giant 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 slow but inevitable threat that builds Steam Eruption stacks throughout the fight. When killed, it explodes for damage equal to all accumulated steam.
The fight at a glance
| Act | Act 1b |
| Location | Underdocks |
| Difficulty | Medium |
| HP | 250 |
| Key mechanic | Steam Eruption |
The rotation
Pressurize (turn 1) → Stomp → Ram → Siphon → Pressure Gun → repeat from Stomp. Steam Eruption stacks continuously. On death: About To Blow → Explode.
Moves
| Move | What it does |
|---|---|
| Pressurize | Builds initial Steam Eruption stacks on turn 1. |
| Stomp | Deals ~15 damage while building steam. |
| Ram | Deals ~15 damage, applies Weak, and builds steam. |
| Siphon | Heals HP while continuing to build steam. |
| Pressure Gun | Heavy attack dealing ~20 damage plus steam buildup. |
| About To Blow | Triggered on death. Gains one turn of invulnerability before exploding. |
| Explode | Final explosion dealing damage equal to all accumulated Steam Eruption stacks. |
How to beat Waterfall Giant
- Kill the Giant as fast as possible to minimize Steam Eruption buildup. The explosion on death is unavoidable, so you need enough HP or Block to survive it. Aggressive, front-loaded decks shine here — every extra turn adds more steam. Have Block or a potion ready for the final explosion turn. Scaling damage that takes time to set up is risky since it lets steam build.
- Speed kills — literally. The faster you win, the smaller the explosion
- Save a Block potion or defensive card for the About To Blow / Explode turn
- The Siphon turn heals the Giant, extending the fight and building more steam
- Front-loaded burst damage is much better than slow scaling in this 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. For the exact HP, Ascension HP and every move’s damage per hit, see the Waterfall Giant monster entry.