Skeleton Key is a special key item that unlocks locked depth exits (the stairs down behind a boss), allowing access to the next dungeon tier.

• Area Unlock: Opens locked depth exits, such as the locked exit of the Prison boss level leading toward the Demon Halls
• One-time Use: Consumed when it unlocks an exit (see Unlock.java)
• Depth-bound: Each key is bound to the depth where its owner was defeated
• Progression Item: Essential for progressing past boss levels

Every boss carries a Skeleton Key and drops it on death:

• Tengu: Dropped after defeating Tengu in the Prison; grants access toward the Demon Halls
• Other bosses: Goo, DM-300, Gnoll King, Spider Queen, Lich, Yog's Eye and others also drop it

• Unlocking Exits: Used on a locked depth exit (the stairs behind a boss) to open the way down
• Consumed on Use: The key is removed from the inventory when it unlocks an exit
• Access Gateway: Required to progress deeper into the dungeon

• Essential Progression: Without this key, the next dungeon tier remains inaccessible
• Timing: Can be saved until ready for the challenging content ahead
• Backup: It's a single-use key, so there's no backup if lost
• Priority: Should be preserved for when you're ready to descend

• Implementation: SkeletonKey.java
• Key system: Part of the key and lock system for dungeon doors
• Level transition: HallsLevel.java

• SkeletonKey.java
• HallsLevel.java
• SkeletonKey strings

• Tengu (source of the key)
• Demon Halls
• Keys
• Items