Mutations

Mutations

Steal Animal Egg mutations and sizes: the seven mutation multipliers, weight scaling, Sakura Incubator Spirit Bloom and how to chase the best pet traits.

7
Mutations
~3x
Top Multiplier

Introduction

Mutations and sizes are the two hidden multipliers that decide how much a pet actually earns in Steal Animal Egg. Every hatch rolls a mutation from a list that includes Silver, Golden, Rainbow and Bloom as natural outcomes on biome eggs, plus rarer event and machine mutations like Spirit Bloom, Parasite and Fractured. Separately, every pet rolls a weight shown in kilograms, and that size scales its income independent of rarity — which is why a huge Silver common pet can genuinely out-earn a plain rare one. The strongest mutations multiply income by around two to three times, but they are hard to secure: Spirit Bloom comes from charging the Sakura Incubator to 100% during the Great Bloom event, Parasite drops from the Hungry Frog event Monster Chest at about a 1.5% chance, and Fractured is bought with 400 Boss Tokens from the Rift boss. This hub explains each mutation, how weight compounds with rarity, and the safest ways to roll, farm and preserve them through fusion.

Mutation Multiplier Reference

MutationMultiplierSourceDifficulty
Silver~1.5xNatural biome egg spawnEasy
GoldenMid-tierNatural biome egg spawnEasy
RainbowHighRarest natural mutationMedium
Spirit Bloom~3xSakura Incubator 100%Hard
Parasite~3xHungry Frog Monster ChestHard (1.5%)
Fractured~2.75xMutation Consumable (400 Boss Tokens)Hard

Mutation Families

B

Silver

natural

Silver — natural starter boost

MultiplierRoughly 1.5x income; shell color changes to silver.
SourceSpawns naturally on biome eggs, fairly common.
StrategyBest first mutation target; any pet with Silver is worth keeping.
Why Start HereSilver is the easiest mutation to farm and gives a real income boost, making it the perfect first goal for new players who want to see their earnings climb without grinding events.
A

Rainbow

natural

Rainbow — rarest natural roll

MultiplierHigh multiplier, well above Silver.
SourceRarest of the natural biomass mutations.
StrategyRare enough that you should never fuse it without identical mates.
Rarity NoteRainbow appears less often than Silver or Golden on the natural table, so when you hatch one, view it as a premium asset and match it with identical values before any fusion.
S

Spirit Bloom

event

Spirit Bloom — Great Bloom prize

MultiplierRoughly 3x income, the strongest tier available.
SourceCharge Sakura Incubator to 100% during the Great Bloom event.
StrategyPlan the incubator grind before the event window closes.
Event TimingSpirit Bloom depends on the Great Bloom event, so check the updates hub for the event window and charge the Sakura Incubator steadily across the season rather than rushing the last day.
S

Parasite

event

Parasite — Hungry Frog drop

MultiplierRoughly 3x income from an event chest.
SourceHungry Frog Monster Chest, about 1.5% drop chance.
StrategyLow drop rate; farm the event while it is live.
Drop MathParasite is powerful but rare — about 1.5% from the Hungry Frog chest — so farm the event regularly and treat every Parasite roll as a jackpot instead of an expected result.
A

Fractured

bis

Fractured — boss token buy

MultiplierRoughly 2.75x income via Mutation Consumable.
SourceRift boss tokens — 400 Boss Tokens per consumable.
StrategyDeterministic but slow; good long-term goal for token farmers.
Token GoalFractured is deterministic once you have 400 Boss Tokens, making it a reliable long-term upgrade for endgame players who already farm the Rift boss; pair it with a heavy pet for best results.
B

Golden

natural

Golden — mid-tier natural boost

MultiplierMid-tier income multiplier, between Silver and Rainbow on the natural table.
SourceSpawns naturally on biome eggs alongside Silver, with a shell color change.
StrategyA dependable farming target; any Golden pet is a keeper when it has decent weight.
Why It MattersGolden is the practical middle ground of natural mutations because it appears far more often than Rainbow but still multiplies income noticeably. Collecting several Golden pets with strong weight gives a reliable income spike for free-to-play players, and matching Golden values before fusing protects the upgrade path.

Core Mechanics

When you hatch an egg, the game independently rolls the pet's rarity, its mutation and its weight, and the final income is roughly the base income multiplied by both the mutation multiplier and the weight multiplier. The natural mutation table on biome eggs produces Silver, Golden, Rainbow and Bloom outcomes with different shell color changes and income boosts, while special mutations come from events and machines: Spirit Bloom requires charging the Sakura Incubator to 100% during the Great Bloom event, Parasite drops from the Hungry Frog event's Monster Chest at about a 1.5% rate, and Fractured is applied with a Mutation Consumable purchased with 400 Boss Tokens from the Rift boss. Weight is displayed in kilograms and acts as a second, independent multiplier whose values are drawn from the hatch — so two identical pets can earn wildly different amounts just because one rolled heavier. Gameboost and community guides describe these values as observed baselines rather than official formulas, and the numbers shift slightly with each update. One critical rule: when you fuse three pets in the Fuse Machine, mismatched mutations can be lost, so players always match mutation values before combining.

Advantages

Understanding mutation multipliers turns random hatching into a measurable economy. A Silver pet is about 1.5x, a Golden mid-tier, and Spirit Bloom or Parasite around 3x — so even a mediocre pet with a top mutation can become your best earner, and knowing this stops you from selling a hidden gem. Weight multiplies further, so tracking kilograms as well as mutation lets you rank every hatch accurately without trusting your gut. Event mutations give free players a real shot at top-tier income: Parasite from the Hungry Frog event and Spirit Bloom from the Sakura Incubator are grindable rather than paywalled, and Fractured only needs boss tokens you earn in-game. The mutation hub also protects you from the biggest money-waster in the game — losing a rare mutation by fusing mismatched pets. Finally, because mutation values are roughly confirmed by the community, planning around them is much safer than guessing at unspecified multipliers, giving you a concrete build path toward a 2-3x farm.

Challenges

Mutations are random and the really good ones are extremely rare: Parasite sits around a 1.5% drop from an event chest, and Spirit Bloom only appears if you fully charge the Sakura Incubator during a limited event window. Community multipliers are observed baselines, not official formulas, so the exact boost can differ from what guides list, and balance patches can silently change values. Weight and mutation roll independently, which adds randomness: you can hatch a hundred eggs and still not see the combination you want. The event-gated mutations also vanish when their event ends, so a player who misses Hungry Frog or Great Bloom has to wait for the next rerun to chase those traits. Finally, fusion is genuinely dangerous — three pets with different mutations can lose the rarer one — so preserving a hard-earned mutation requires careful sorting and sometimes means fusing less often, which slows your rarity climb.

Frequently Asked Questions

What is the strongest mutation?+
Spirit Bloom and Parasite are tied at the top with roughly 3x income multipliers, followed by Fractured at about 2.75x and then the natural Silver, Golden and Rainbow mutations. Spirit Bloom requires charging the Sakura Incubator to 100% during the Great Bloom event, Parasite drops from the Hungry Frog event Monster Chest at about 1.5%, and Fractured is bought with 400 Boss Tokens. For most players, any of the 2x-plus mutations on a high-weight pet is a game-changing find.
How do sizes and weight work?+
Every pet rolls a weight shown in kilograms when it hatches, and that weight acts as an independent multiplier on income. Because weight stacks on top of rarity and mutation, a huge common pet with a good mutation can out-earn a plain rare pet. Check the weight display whenever you hatch; if a solid mutation arrives on a heavy pet, that is usually worth keeping and building around rather than fusing or selling.
Can I lose a mutation when fusing?+
Yes. When you put three pets into the Fuse Machine, mismatched mutations can be lost during the merge, which would destroy a valuable Silver, Golden or event mutation. Always sort your duplicates by mutation and only fuse three pets with identical mutation values. If you only have one copy of a top mutation, keep it out of the machine entirely and wait for matching duplicates before upgrading it.

Quick Tips

💡

Hatch in bulk from the highest biome you can reach because rare mutations appear more often on exotic eggs. Silver and Golden are the practical farm targets on natural biome eggs; Rainbow is rarer, so treat it as a bonus. Charge the Sakura Incubator during Great Bloom for the ~3x Spirit Bloom if the event is live.

💡

Never fuse mismatched mutations. The Fuse Machine is a great rarity path, but three pets with different mutation values can erase the rarer one. Use the sort-by-mutation view, fuse identical values only, and keep a top mutation like Spirit Bloom out of the machine until you have matching duplicates to upgrade.

💡

Treat weight and mutation as a combined score. A 1.5x Silver on a heavy pet beats a 2x mutation on a featherweight pet more often than you would expect, because weight multiplies everything. When comparing offers or planning keeps, evaluate both numbers together instead of only chasing the flashiest mutation badge.

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