Underground Labyrinth · Stage 50
Underground B50F
地底50層
Underground B50F is a Battle Cats stage in Underground Labyrinth: The Grand Deep. It costs 400 energy and sends 5 enemy spawn lines — led by Otta-smack-u as the boss — against a 600,000 HP enemy base, and clearing it rewards 2,256 XP. Its enemies carry the Black trait, so cats that target it do the most work here.
Data updated: 2026-08-31
400Energy Cost
2,256XP Reward
600,000Enemy Base HP
4,500Stage Length
5Max Enemies
9.1Difficulty
Enemy spawns (5)
| Enemy | Strength | Count | First Spawn | Respawn | Base HP Trigger | Notes |
|---|---|---|---|---|---|---|
 Otta-smack-u | 400% | 3 | 10s | 20s~23.3s | 100% | — |
 Those Guys | 3000% | ∞ | 16.7s | 3.3s~10s | 100% | — |
| Otta-smack-u | 400% | 10 | 16.7s | 10s~13.3s | 99% | — |
| Otta-smack-u | 100% | 1 | 16.7s | — | 99% | Boss |
 Dark Otter | 150% | 2 | 20s | 46.7s~50s | 99% | — |