The Gloom Worm final boss fight
The fight at the end of The Forgotten Path has been the developers’ showpiece since the prototype. What is public about it comes mostly from the demo patch notes, so read the mechanics below as the demo version unless a line says otherwise.
How the fight came together
Prototype, January 2025
Rebuilt from the ground up
The studio called the first version one of the roughest parts of its prototype, then replaced it with a worm “complete with 4 evolving states, a dozen nightmarish limbs, and a colossal body to blast to bits!” Announced in Team Lazerbeam devlog on itch.io: Shroom and Gloom Mega Updates, 28 January 2025
Steam demo, July 2025
Cosmic Horror and edible limbs
Three demo patches in a row reworked the fight. One line reads “Cosmic Horror added to the Gloom Worm boss fight! Yipes!”, another adds guts to its limbs, and the notes describe intent changes meant to make the fight less overwhelming. Patch notes in Steam announcement: 2 months of demo updates lead to this! Shroom and Gloom 0.4.71 is here!, 11 July 2025
Steam demo, August 2025
Its own music
The fight got a new song, flagged by the developers as still a work in progress. Listed in Steam announcement: 80K Wishlists, Demo update and NorthernLion! Shroom and Gloom Aug 2025 Dev Log!, 19 August 2025
Early Access
End of The Forgotten Path
Players finishing their first Early Access runs describe the last boss as the Gloomworm, and one noted that it matches the art on the Gloom Slayer achievement. Reported in Steam discussion: Achievements bugged?, 13 September 2026
What the patch notes say the fight does
None of this has been restated for Early Access, and a year of development sits in between. It is still the only rulebook the developers have published for this fight.
| Piece of the fight | Demo patch note | What it means for a run |
|---|---|---|
| The limbs | “Limbs apply vulnerable on the main body on death” | Killing a limb softens the body, so the limbs were not just a distraction in that build. |
| Cosmic Horror | Changed when Cosmic Horror will increase costs, with food and curses no longer triggering it | The curse makes your cards cost more. Food and curse cards stopped setting it off. |
| Inescapable | “Cosmic Horror now added to the top of your deck rather than being auto drawn” | You see it coming as the next draw instead of having it forced straight into your hand. |
| Evolving | “Made gloom worm face no longer jump on evolution.” | Confirms the evolving stages; attacks carrying over between stages was noted for evolving enemies in the same notes. |
All four lines: patch notes in Steam announcement: 2 months of demo updates lead to this! Shroom and Gloom 0.4.71 is here!, 11 July 2025
The achievement that does not always pop
Steam credits 0.1% of players with Gloom Slayer, and Steam’s internal name for it is FLAG_KILL_GLOOMWORM. On launch day a player wrote that they had “beat the gloomworm 3 more times and still have not gotten the achievement” in Steam discussion: No Achievement For Beating game?!?!, 10 September 2026, and Team Lazerbeam has called misfiring achievements a known issue it will fix. The bosses overview lines this figure up against the rest of the run, and the achievements page covers every achievement without a public description.
After it falls
What happens next has players stuck rather than celebrating. The ending page collects what they report finding beyond the fight and the theories about a hidden way through. The walkthrough covers the route to the worm, and resting and camp covers how to arrive with enough health to spare.