Every critter in Steal an Egg earns cash each second, even while you are offline, but a mutation is the fastest way to multiply that number. Mutations attach to pets through eggs rather than being applied directly, so you hunt for mutated eggs and hatch them to pull the special variant.
Quick answer: There are eight mutations. Luminous (10x) is the strongest, followed by Rainbow, Parasite, Fractured, Golden, Spirit Bloom, Bloom, and Silver. Some roll from eggs, others come only from limited events.
Every mutation and its income multiplier
The table ranks all eight mutations by their income multiplier, from highest to lowest. Luminous and Rainbow are the best variants to chase right now, but even the weaker ones raise a pet’s worth, so keep the mutated critters you find.
| Mutation | Multiplier | Available now | Main source |
|---|---|---|---|
| Luminous | 10x | Yes | Luminous Egg (1% hatch) |
| Rainbow | 3.5x | Yes | Egg spawn or 1% hatch |
| Parasite | 3x | No | Parasite Egg (event) |
| Fractured | 2.75x | Yes | Mutation Consumable |
| Golden | 2.5x | Yes | 4-in-100 hatch roll |
| Spirit Bloom | 2.5x | No | Sakura Incubator (event) |
| Bloom | 1.25x | No | Sakura event reward |
| Silver | 1.2x | Yes | 6% hatch roll |
Natural mutations you can roll any time
Natural mutations are permanent and appear at random when you open eggs or pick up an egg that already spawned with an aura. Rainbow, Golden, and Silver fall into this group, and the Luminous variant works the same way through its own dedicated egg.
Luminous (10x)
Luminous is the top-tier variant. Hatch a Luminous Egg for a 1% chance to pull the mutation onto whatever pet the egg produces. Because the multiplier is 10x, a single lucky roll can outpace every other aura in your pen.
Rainbow (3.5x)
A Rainbow Egg can appear in any monster’s nest once the night ends, marked by a glowing rainbow aura around the shell. Open it to get a Rainbow pet based on that egg’s type, so a Rainbow Shark Egg gives a Rainbow-mutated Shark at 3.5x base income. You can also land Rainbow on a normal hatch at a 1% chance.
Golden (2.5x) and Silver (1.2x)
Golden shows up automatically on a pet during hatching with a 4-in-100 chance and adds a 2.5x multiplier. Silver is the most common aura, appearing on roughly 6% of hatches for a modest 1.2x boost. Neither needs an event, so they fill your pen steadily as you open eggs.
Event and shop mutations
The remaining mutations are tied to specific events or the Boss Shop. They are only reachable while their content is live, so plan around the active event window.
Parasite (3x)
Parasite does not roll from normal eggs. You earn Parasite Eggs from Monster Chests during the Hungry Monster event, then hatch them to get the 3x variant. Collect infected eggs from the map and feed five to the Hungry Frog for a chance at a chest.
Fractured (2.75x)
Fractured is the only mutation you apply on purpose from the shop. Buy the Mutation Consumable from the Boss Shop for 400 Boss Tokens, earned by defeating the Rift boss, then use it on an egg placed on your farm. Each consumable gives that egg a 10% chance to hatch Fractured.
Spirit Bloom (2.5x) and Bloom (1.25x)
Both Sakura variants come from the Cherry Blossom zone during the Sakura event. Charge the Sakura Incubator with Sakura Crystals, place your best pet inside, and roll. Maxing the charge doubles the Spirit Bloom chance from 5% to 10%; Bloom is the common result and Spirit Bloom is the rare jackpot.
Because you choose which pet enters the incubator, feed it your highest base-income pet with the best size roll, never a spare.
How mutations stack with pet size
A mutation is only one part of a pet’s earnings. Size, shown as a weight in kilograms on the pet card, is rolled separately, which is why the same pet can appear as a Golden Giant or a plain Huge with no aura at all. Final income combines both:
Final Income = Base Income × Mutation Multiplier × Size MultiplierSize scales hard at first, then slows down. Above 125x the pet’s hidden base weight, the game applies diminishing returns, so a pet at 100x base weight earns about 17x its base value, 200x earns roughly 23x, and 1000x lands near 45x. Bigger eggs still pay more, but the gain per kilogram shrinks the heavier they get.
Which eggs to grab first
When a new day starts, all eggs reset and larger ones can spawn in different biomes. Since the aura is visible on the shell before you pick it up, patrol the nests and prioritize a large Rainbow-mutated egg over smaller mutated eggs from other areas, because a bigger Rainbow pet earns far more cash per second.
To confirm a mutation landed, check the pet after it hatches. The variant appears as a colored aura on the model, and the money-per-second value on its pet card will read higher than the plain base rate shown in the Pet Index. If the card matches the base number with no aura, the roll came up empty and you will need another egg.
