Spelunker Hat is a passive item in The Binding of Isaac: Rebirth (TBOIR)
Reveals on minimap what type of rooms are adjacent to the room Isaac is in (even if Isaac hasn't been to those rooms yet). Also identifies adjacent Secret Rooms and Super Secret Rooms including the discovery sound effect.
Character has a miner hat on him, with a green light:
- "Spelunker" comes from the term "Spelunking" which means "cave exploration"