Mutations in Build a Base and Steal change how much a pet is worth. Every pet earns Cash each second, and a mutation multiplies both that earning rate and the pet’s sale value. Four mutations exist right now, and each one applies a fixed multiplier that stacks the income you collect from the affected critter.
Quick answer: A pet can carry one mutation at a time. Golden gives 1.5x, Cosmic gives 2x, Inferno gives 3x, and Admin gives 4x to both sale value and Cash income. Admin is the strongest and only appears during an Admin Abuse event triggered by the developers.
All pet mutations and their multipliers
Each mutation raises a pet’s sale value and its Cash earning rate by the same multiplier. The higher the multiplier, the more income that single pet produces every second and the more you get if you sell it.
| Mutation | Multiplier | How it appears |
|---|---|---|
| Golden | 1.5x | Small chance on a Pet Roll |
| Cosmic | 2x | Cosmic Invasion event |
| Inferno | 3x | Volcano event |
| Admin | 4x | Admin Abuse event (developer-triggered) |
How to get each mutation
Two paths create mutated pets. Some come from the Pet Roll directly, and others attach to pets already sitting in your base while a special event is running on the server.
Golden mutation
Golden is the only mutation tied to rolling rather than an event. Each time you use a Pet Roll, there is a small chance the critter appears already Golden, which you can then buy with Cash. Rerolling is currently the only way to obtain it, so keep rolling if you want the 1.5x boost.
Cosmic mutation
During the Cosmic Invasion event, alien spaceships can abduct pets from your base and drop them back with the Cosmic mutation applied. Keeping several pets in your base raises the odds that a ship grabs one of them. The event runs on rotation but can also be started manually by the developers.
Inferno mutation
When the Volcano event is active, the spawned volcano can hand out Inferno-mutated pets, and there is also a small chance that pets already in your base gain the Inferno mutation. Like the Cosmic Invasion, the Volcano is part of the game’s event rotation. Inferno carries a 3x multiplier, the second highest available.
Admin mutation
Admin only appears during an Admin Abuse festivity, which the developers typically host after an update goes live. The Admin mutation may or may not be switched on during that event, so it is not guaranteed. When it does appear, it grants the top 4x multiplier to both sale value and earning rate. Watch the official Build a Base and Steal Discord to know when an Admin event is running.
Best mutation for income
Admin is the best mutation available. It quadruples a pet’s sale value and multiplies its Cash earning rate by 4x, ahead of Inferno’s 3x, Cosmic’s 2x, and Golden’s 1.5x. Because it only shows up when the developers turn it on during Admin Abuse, joining the server sessions when those events run is the only reliable way to earn it.
Mutation rules and limits
A few fixed rules decide how mutations behave across your collection.
- A pet can hold only one mutation at a time.
- Multiple pets in your base can each gain a mutation during a single event, so a busy base benefits more.
- There is currently no way to move a mutation from one pet to another.
Because the event-based mutations attach to pets you already own, the practical move is to keep your pen full before a Cosmic Invasion, Volcano, or Admin Abuse begins. More pets in the base means more chances for a higher multiplier to land, and a single Admin, Inferno, or Cosmic pet can noticeably lift your Cash per second.
