Rarity System Overview
Rarity is the primary stat bucket for brainrots in Drill Blocks for Brainrots. It determines base CPS, sell price, spawn weight, and often rebirth requirement eligibility. Color-coded nameplates make tiers easy to spot at a glance when drilling in crowded servers.
Higher rarity always means higher baseline income — but mutations and traits can let lower rarities outperform vanilla units above them. Read mutations & traits before sacrificing a Gold Uncommon for a plain Rare.
Common & Uncommon
Common brainrots dominate surface and tutorial zones. They teach placement mechanics and fill early plot slots. Base CPS is low, but five Commons generating simultaneously fund your first drill upgrade faster than hoarding one Uncommon.
Uncommon units appear once you break the first few zone floors. Keep them until Rare drops arrive, then recycle slots. Do not sell Uncommons if your plot has empty pedestals — any placed unit beats inventory idle time.
Rare & Epic
Rare marks the start of meaningful mid-game. CPS jumps noticeably; many rebirth gates ask for at least one Rare owned or placed. Farm Rare tiers in mid-depth zones once your drill breaks floor blocks without struggle.
Epic brainrots anchor mid-to-late plots before Legendary hunting. Several rebirth cycles require Epic ownership. Prioritize Epic drops with mutations during event windows — a Diamond Epic is a long-term keeper.
Legendary & Mythic
Legendary units come from deep zones and high-tier events. They define competitive plots and often appear in tier list S-ranks. Expect low spawn rates — long sessions or event bursts are normal.
Mythic sits above Legendary in base CPS and spawn rarity. Some Mythics tie to specific worlds on the worlds page. Drill power gates matter more here than luck alone.
Primordial & Eternal
Primordial is end-game chase content — the tier before the absolute ceiling. Spawn rates are extremely low; rebirth-boosted accounts farm Primordials during trait events for mutation stacking.
Eternal is the top rarity band. Eternals have the highest base CPS and flex value. A Rainbow Eternal with a top trait is the theoretical best single plot slot in the game. See how to get rare brainrots for farming tactics.
Rarity vs Zone Depth Table
Approximate spawn bands (shift with patches):
| Rarity | Typical Zone Depth | Relative Spawn Rate |
|---|---|---|
| Common | Surface – Floor 1 | Very High |
| Uncommon | Floor 1 – 2 | High |
| Rare | Floor 2 – 4 | Medium |
| Epic | Floor 4 – 6 | Low |
| Legendary | Floor 6+ / Events | Very Low |
| Mythic | Deep Worlds | Extremely Low |
| Primordial | Deepest Worlds | Ultra Rare |
| Eternal | End-game / Events | Chase |
Cross-reference exact floor names on the map page.