All 4 Pet Mutations in Build a Base and Steal

Pet mutations are optional tags on individual pets that multiply both passive cash generation and the cash you get when you sell that pet. Each pet holds one mutation at a time, so the multiplier you roll or earn during an event sticks to that pet until you sell it or lose it in a steal.

How mutations change your pets

A mutated pet earns more money per second while it sits on your base, and it sells for more cash if you cash it out. The boost uses the same multiplier for both numbers, so a stronger mutation is worth keeping on a high-base pet you plan to defend.

You cannot stack two mutations on one pet. If you want a higher tier, you need a new roll result or a fresh pet from an event window.

Multiplier tiers and what to expect

Golden is the everyday roll outcome. Cosmic, Inferno, and Admin are event-tier jumps that are harder to land but pay off harder on both income and resale.

Rolling for Golden

Head to the Egg Mystery station on your base and run Pet Rolls. Golden is the mutation most players see from normal rolling, so this is where most bases pick up their first multiplier.

Luck and rebirth bonuses can tilt roll odds, but exact rates are not published. If rolls feel dry, rebirth and luck upgrades are the usual long-term fixes rather than chasing one golden pet on a single session.

Hunting event mutations

Cosmic, Inferno, and Admin mutations come from short live-event windows rather than steady grinding alone.

• Cosmic Event: Primary source for Cosmic pets. Some community guides also report rare Cosmic hits straight from Pet Rolls, so keep rolling if you are already at the Egg Mystery station when the event is live.
• Volcano Event: Main path for Inferno. Guides also mention Inferno pets spawning naturally inside the volcano during the event, which can be a faster grab than rolling alone.
• Admin Abuse Event: Only source for the Admin mutation. These developer-hosted bursts are short and irregular, so they are easy to miss if you are not watching for announcements.

Community Discord pings and in-game event banners are the practical way to catch these windows. There is no fixed public schedule to camp on.

Keep, sell, or steal

Put the highest multiplier on pets with strong base rarity stats. A 3x Inferno on a weak pet still beats a plain pet, but the same mutation on a pet that already prints cash scales much harder.

Selling a mutated pet still applies the mutation multiplier to the sale payout, so cashing out a mid-tier golden pet is fine early on. Later, you usually want event-tier pets on your defense line.

Stealing works on mutated pets too. A rival base might already be holding the Cosmic or Inferno you skipped, so defense and rebirth matter once mutations show up in the steal loop.

Common mistakes

• Rolling only during events and ignoring Golden on normal days when rolls are cheaper to spam.
• Parking your best mutation on a pet you plan to sell immediately, then wondering why income barely moved.
• Assuming you can add a second mutation after Golden already landed. You need a new pet or a new roll result.
• Sleeping through Admin Abuse windows and expecting a 4x pet from standard rolls alone.