What Is the Collection Bonus?
Beyond individual mutated brainrots on your plot, Drill Blocks for Brainrots tracks a mutation collection progress bar per mutation type (Gold, Diamond, Galaxy, Lava, Rainbow). When you collect 75% of all brainrots that can roll a given mutation, you unlock a permanent +0.5× cash multiplier for that mutation line.
These bonuses stack across mutation types — collecting Gold, Diamond, and Galaxy sets yields +1.5× on top of rebirth and trait multipliers. See exact mutation stats on the mutations page.
Exact Multipliers Per Mutation
| Mutation | Unit Multiplier | Collection at 75% |
|---|---|---|
| Gold | 1.25× | +0.5× global cash |
| Diamond | 2× | +0.5× global cash |
| Galaxy | 3× | +0.5× global cash |
| Lava | 7× | +0.5× global cash |
| Rainbow | 10× | +0.5× global cash |
Collection progress counts unique brainrot entries in the mutation dex — not duplicate units in inventory. Check your in-game collection UI for percentage bars.
Fastest Path to 75%
- Start with Gold — commons and uncommons fill Gold slots fastest in starter worlds.
- Move to Diamond during mid-game Rare/Epic farming in Candy or Light worlds.
- Save Galaxy/Lava/Rainbow for deep zones and admin abuse sessions when mutation showers spike.
- Equip mutation-luck artifacts such as Echo of the Forgotten Name (+8% mutation chance) while filling dex gaps.
Pair collection sessions with rare brainrot farming so you upgrade your plot while filling dex entries.
Collection vs Plot Priority
A 75% Gold set bonus helps every brainrot on your plot — even vanilla units. Early game, filling Gold dex is often better ROI than chasing one Rainbow Legendary. Late game, Rainbow collection is the long chase but pays permanently.
Use the CPS calculator to compare a new plot unit against the global bonus from completing a mutation line.
Synergy With Other Systems
- Traits — Collection bonuses multiply base CPS; traits still apply per-unit. Read mutations & traits.
- Rebirth — Collection progress typically persists through rebirth unlike drill tiers.
- Artifacts — Mutation-luck artifacts speed dex fills — artifacts guide.