Mutations are random modifiers on enemies. They start in the Stone Layer at 10 km. A mutated enemy is harder, and most corpses sell or burn for more. Since 3 October 2026, a second hit of the same mutation refreshes the timer instead of stacking. That update also stretched Fire from 6 seconds to 8 and Toxic from 8 seconds to 16.
| Mutation | First seen | Effect | Sell | Fuel |
|---|---|---|---|---|
| Void | Clay Layer | Tankier, and 25% faster since 29 August 2026 | 1.5x | Not listed |
| Giant | Fossil Layer | Bigger and tankier, 0.75x speed | 1.5x | 3x |
| Stone | Crystal Layer | 0.75x speed. Only a pickaxe or explosives hurt it. It explodes on death. Since 22 August 2026 it drops an ore or gem. | Not listed | Not listed |
| Toxic | Toxic Layer | 16 seconds, 1 to 10 damage per second, healing halved while active | 1.5x | Not listed |
| Frozen | Frozen Layer | Slow for 4 seconds. Enemies page says 25%. Layers page says 50%. | 1.5x | Not listed |
| Electric | The Abyss | 1.5x speed. Shocked players get a 50% speed boost since 29 August 2026 | 1.5x | 2x |
| Fire | Glowing Core | Burn for 8 seconds at 2% max health per second | 1.5x | 2x |
| Golden | Money Fog, or Gunsmith level 3 | Not a layer mutation | 3x | Not listed |
Stone drops
| Size | Examples | Drop weights |
|---|---|---|
| Small | Goblins, Spiders, Bat Minions, Crazy Miners, Bandit Miners | Coal 50%, iron 30%, gold 15%, diamond 4%, emerald 1% |
| Medium | Vampires, Goblin Knights | Iron 35%, gold 35%, diamond 20%, emerald 8%, ruby 2% |
| Large | Goblin Lords, Mole Men | Diamond 60%, emerald 35%, ruby 5% |
| Huge | Goblin Champions, Widows | Emerald 80%, ruby 20% |
The Black Hole Gun deals explosive damage and can hurt Stone enemies. Mounted Gunner shots spark on Stone targets and do not land. Demolitionist is the class built around the explosives that work on them.
Using the corpses
Burn Giant corpses when the tank is low. They are listed at 3x fuel. Electric and Fire corpses are 2x. Golden corpses are the sell, at 3x coins. A Money Fog also doubles every item's sell price while it is active, which is separate from the Golden multiplier.
Goblin King can recruit goblins. The 22 August 2026 notes say a recruited mutated goblin passes that mutation on when it hits, for every mutation except Stone.
Past 100 km, regular enemies are described as spawning with both Void and Fire. That is a large part of why Infinite Mode damage spikes.