Steal a Brainrot Index — Completion Rewards Explained
Completion thresholds and rewards
| Index set | Needed | Reward |
|---|---|---|
| Default (Normal) | 75% of all brainrots | +0.5x base multiplier |
| Gold | 75% of all brainrots | +0.5x base multiplier and the Gold base skin |
| Diamond | 75% of all brainrots | +0.5x base multiplier and the Diamond base skin |
| Rainbow | 75% of all brainrots | +0.5x base multiplier and the Rainbow base skin |
| Candy | 100% of brainrots added before 25 Jul 2025 | Candy base skin |
| Lava | 100% of brainrots added before 23 Aug 2025 | Lava base skin |
| Galaxy | 100% of brainrots added before 27 Sep 2025 | Galaxy base skin |
| Yin Yang | 75% of brainrots added before 15 Nov 2025 | Yin Yang base skin |
| Radioactive | 75% of brainrots added before 3 Jan 2026 | Radioactive base skin |
| Cursed | 60% of brainrots added before 21 Feb 2026 | Cursed base skin |
| Divine | 60% of brainrots added before 18 Apr 2026 | Divine base skin |
| Cyber | 60% of brainrots added before 13 Jun 2026 | Cyber base skin |
Seasonal sets are capped to brainrots that existed before that mutation's cut-off date, which is what makes them completable at all — otherwise every new update would push the target further away.
Wiki data pulled:
Why the thresholds dropped over time
The earliest seasonal sets (Candy, Lava, Galaxy) demanded 100% of everything released before their cut-off. As the roster grew past five hundred entries that stopped being realistic, and the newer sets ask for 60%. If you are choosing which set to chase, the recent ones are dramatically cheaper per reward.
The unobtainable problem
273 brainrots in the full list are marked unobtainable — retired machines, past events, limited stock. Because permanent sets only ask for 75%, missing those does not lock you out, but it does mean the last quarter of any index is the expensive quarter. Check what a brainrot's status is before you trade for it purely to fill an index slot.
Index multipliers stack with rebirths
Each +0.5x from an index applies on top of the rebirth multiplier, which is why late-game bases earn so much more than their raw brainrot income suggests. Model a specific setup in the income calculator — the rebirth dropdown there covers the rebirth half of the equation.