Mutations are rare, permanent variants a pet can spawn with — a layer of power that stacks on top of its rarity and rank. A mutated pet keeps its mutation forever, and the bonuses can be substantial, which is why mutation hunting is one of the longest-tail chases in the game. This guide covers every mutation, what each one does, and when it's actually worth farming for them.
How mutations work
A pet rolls its mutation (or none) when it spawns. The odds are brutal on a normal day, and when a pet does mutate, the stat bonus is applied multiplicatively — so a Shiny on a high-rank pet multiplies an already-large number. You can't add a mutation to a pet you already own; you have to catch a new one that rolled it.
The mutations
| Mutation | Bonuses | Base chance |
|---|---|---|
| Shiny | +10% Attack · +30% Crit Rate · Crit Damage fixed at 200% | 0.01% |
| Huge | +40% Attack · +40% HP | 0.001% |
| Bloodlit | +10% Crit Rate · +100% Crit Damage | Bloodmoon only |
| Fairy | +25% Damage Reduction · +25% Cooldown Reduction | Not yet documented |
| Corruption | Cosmetic only — no stat bonuses (yet) | Not yet documented |
Shiny is the workhorse: the most attainable mutation and a clean offensive boost, with crit damage locked to 200%. Huge is the rarest base-game roll and the best all-round stat line — +40% to both Attack and HP. Bloodlit is a pure crit-damage monster but only exists during a special weather event. Fairy trades offence for survivability, and Corruption is currently cosmetic with no combat effect.
Bloodmoon Weather: the mutation window
Mutation rates are tiny on a normal day, but the rare Bloodmoon weather event changes the math entirely. During a Bloodmoon, every mutation gets far more likely, and it's the only time Bloodlit can spawn at all:
| Mutation | Normal | Bloodmoon |
|---|---|---|
| Shiny | 0.01% | 0.3% (30× more likely) |
| Huge | 0.001% | 0.013% |
| Bloodlit | — | 0.5% |
If you want to farm mutations, a Bloodmoon is the time to do it — Shiny becomes thirty times more likely and Bloodlit unlocks. Outside of one, mutations are best treated as a lucky bonus rather than a target.
Are they worth chasing?
- Don't grind for them on a normal day. At 0.01% and lower, you'll get more value from ranking up the pets you already have.
- Do farm during a Bloodmoon. The boosted rates make it the one window where catching extra is genuinely worth it — especially for a shot at Bloodlit.
- Match the mutation to the role. Huge for an all-round carry, Shiny or Bloodlit for a crit build, Fairy for a tanky survivor.
For the full interactive breakdown — every bonus, the Bloodmoon rate comparison, and icons — see the mutations page on the wiki. New to the game? Start with the Beginner's Guide.