The official Roblox description confirms that mutations are part of the discovery system. IGN's August 2026 guide lists six named mutations and their reported sources.

Mutation sources

MutationReported way to get it
SilverChance when hatching an egg or using the Fuse Machine
GoldChance when hatching an egg or using the Fuse Machine
RainbowChance when hatching an egg or using the Fuse Machine
BloomChance when placing an egg in the Sakura Incubator
Sakura BloomLower chance in the Sakura Incubator
MonstrousLow chance from a Monster Chest

Bloom and Sakura Bloom are associated with the Cherry Blossom Biome in the source. Treat the listed routes as reported until the current game confirms them.

Do mutations have fixed multipliers?

Not according to the available evidence. The guide explicitly avoids publishing one fixed modifier because the observed increase can differ between pets. A Silver mutation on one pet is not enough to establish the Silver value for every pet.

Record the pet, its base Index income, its weight and the mutated income if you are testing a multiplier. Until there is a repeatable sample, publish the observation rather than a universal percentage.

Fuse Machine requirement

The available guide reports that at least three of the same pet are needed to use the Fuse Machine. It also describes the machine as a way to increase chances of the three standard mutations, while the Sakura Incubator is needed for Bloom and Sakura Bloom. Confirm the current interface and requirements before spending valuable pets.