As you build bridges and explore different areas of the map, you’ll see some brainrots with distinct appearances and a higher earning rate than their base variants. These are called mutated brainrots, and this Build Bridge to Brainrots mutations guide will tell you everything you need to know about them. So, let’s get started.
All Build Bridge to Brainrots Mutations & Their Multipliers
| Mutation | Multipliers |
|---|---|
| Gold | Increases the brainrot’s earning rate and sale value by 1.5x. Gold-mutated brainrots will have a completely yellow appearance, and the text ‘Gold’ appears above their name. |
| Diamond | Increases the brainrot’s earning rate and sale value by 2x. Diamond-mutated brainrots will have a completely cyan appearance, and the text ‘Diamond’ appears above their name. |
| Lava | Increases the brainrot’s earning rate and sale value by 2.5x. Lava-mutated brainrots will have a lava-like appearance, and the text ‘Lava’ appears above their name. |
| Galaxy | Increases the brainrot’s earning rate and sale value by 3.5x. Galaxy-mutated brainrots will have a completely purple appearance, and the text ‘Galaxy’ appears above their name. |
| Rainbow | Increases the brainrot’s earning rate and sale value by 5x. Rainbow-mutated brainrots will have a dynamic appearance, and their colors will change between Red, Yellow, Orange, Blue, and Purple. The text ‘Rainbow’ also appears above their name. |
How to Get Mutated Brainrots in Build Bridge to Brainrots

Now that you know what each mutation looks like and how it will affect the earning rate of a brainrot, here’s how you can get brainrots with mutations in Build Bridge to Brainrots:
- Find and collect from the different areas: Brainrots have a random chance of spawning naturally with a mutation in all areas of the map. Gold, Diamond, and Lava mutations are common and have a high spawn rate. Galaxy mutation has an even lower chance to spawn. The Rainbow mutation is the rarest in the game right now and has the lowest spawn chance.
- Use the Mutator Machine: There is a Mutator machine in the Legendary area of Build Bridge to Brainrots. This machine can apply a mutation to a brainrot if you add two similar brainrots to the machine. Depending on the rarity and mutation of brainrots you add to the machine, you’ll have to wait a few minutes and pay some Cash as well.
How to Use the Mutator Machine in Build Bridge to Brainrots

The Mutator machine, located in the Legendary area, can be used to apply mutations to brainrots and merge two brainrots into one. Before you can use the machine, you’ll have to unlock it for $5M Cash.
After unlocking, bring two exact same brainrots and add them to the machine to start the mutation process. Hold both the brainrots one after the other and simply walk up to the machine to add them to the machine. After that, interact with the machine again to start the process.
Here’s how you can get all the mutations from the machine:
- Gold: Add two of the same normal brainrots to get a Gold variant.
- Diamond: Add two of the same Gold brainrots to get a Diamond variant.
- Lava: Add two of the same Diamond brainrots to get a Lava variant.
- Galaxy: Add two of the same Lava brainrots to get a Galaxy variant.
- Rainbow: Add two of the same Galaxy brainrots to get a Rainbow variant.
Build Bridge to Brainrots FAQs
Rainbow is currently the best mutation in Build Bridge to Brainrots because it applies the highest money multiplier to the brainrot (5x).
No, brainrots can only spawn with a single mutation, and there’s no other way to add a second mutation to a brainrot.
The Mutator Machine is in the Legendary area. You can use the Mutator Machine to merge your two mutated brainrots into one with a better mutation.
No, Build Bridge to Brainrots does not have any codes right now.
If you're also nuking walls for brainrots, make sure you check out our Nuke for Brainrots Mutations Guide. We also have a dedicated Roblox section full of codes and helpful guides for all top Roblox games.