生物群落鑰匙 are 困難模式 items used to open 生物群落寶箱s. Though unusable until 世紀之花 is defeated, they can be dropped at any time during Hardmode. On the 電腦版, each key has a 0.04% (1/2500) chance of dropping from an 敵怪 in the key's respective 生物群落. On the 主機 and 移動 versions, they are not dropped directly and must be crafted from 生物群落鑰匙模具s.
Any enemy in the biome that will drop coins when killed can drop the key, not just biome-exclusive enemies. Keys cannot be dropped by 流星頭s (which don't drop coins in 困難模式), enemies spawned by a 雕像, 小動物, or any enemy spawned by a pillar in the 月亮事件. Additionally, enemies in Hybrid Biomes have a chance to drop any key from its composite biomes. The biome is determined by which biome the player currently is in, not the enemy killed.
Any Biome Key dropped prior to defeating Plantera will display the tooltip "It has been cursed by a powerful Jungle creature" and will be unable to open its respective chest until Plantera is defeated. However, cursed keys are usable in worlds where Plantera has already been defeated. Biome Keys are consumed upon use.
- No longer requires Key Molds; Biome Keys drop from enemies again.
- No longer drops from a 流星頭.
- Can no longer open a Biome Chest until 世紀之花 is defeated.
- 1.2.1：No longer drops from enemies, instead crafted with a mold dropped in the same way.