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Gunk Worm: surviving the third stage

Nothing official describes this fight yet. What players know comes from people who have beaten it, and one detailed breakdown on the Steam forum explains why so many runs die in its last stage.

A red cavern fight against a tall long-legged mushroom and four smaller creatures
A fight in a red cavern against a tall, long-legged mushroom and four smaller creatures. Screenshot: Team Lazerbeam / Devolver Digital, via the Steam store page.

The loop that ends runs

The damage people complain about is not the worm hitting you. It is two curse cards working together, as laid out by a player who has cleared the fight several times in Steam discussion: The Gunkworm thoughts, 12 September 2026:

  1. You play a card.
  2. Shivering Horror discards a random card from your hand.
  3. If that card is Creeping Horror, it refuses to leave and you take 15 damage instead.
  4. Creeping Horror is still in your hand, so the next card you play can hit it again.
You’ve just lost 45 HP for playing four cards, and you haven’t even reached the enemy turn.
From The Gunkworm thoughts on the Steam forum

That also turns the usual fix upside down. Drawing and generating more cards normally rescues a hand that keeps getting discarded, but here every extra card you play is another roll that can land on Creeping Horror. A deck built to churn through cards can make the stage worse, not better.

What the stage throws at you

These are one player’s figures from their own runs, not published numbers, and a patch can change any of them.

666

Gunk Worm health in stage 3

4 × 75

Minion health on the board

32

A Gunk Worm hit

×2

Damage once it uses its teamwide Inspire

The minions are not idle either. The same post lists damage, card theft and shielding among what they do, which is why the fight feels like several checks at once rather than one big health bar.

The counter players are testing

Stubborn is a card keyword whose listed benefit is a cheaper card, but it also comes with its own “would be discarded” behaviour. The idea is that making Creeping Horror Stubborn might cancel its 15-damage trigger. A reply in the same thread passes on that “someone said that the intended solution is indeed to make creeping horror a stubborn card”, and the original poster names Thick Sludge as a card that adds Stubborn.

Before you get there

  • Arrive with health to spare. The fights before this one can go smoothly and still leave you short for a stage that can take a hundred health in a turn; resting and camp covers the trade-offs.
  • Plan for minions. A deck that only scales single-target damage is racing the Inspire timer with four extra health bars in the way. Cards and the two decks explains how cards grow during a run.
  • Expect the achievement to lag. Steam credits 5.7% of players with Gunk Slayer, and players have reported the kill not registering. The bosses overview explains why.

The other final boss is the Gloom Worm at the end of The Forgotten Path.