- For other uses, see Penny (disambiguation).
Flat Penny is a trinket first added to the Wrath of the Lamb expansion for the original game, and also appear in the Rebirth remake. It is a silver-colored coin appears to be flatten.
- Gives a 50% chance of spawning a Key upon collecting a coin.
- Keys dropped through use of this trinket are treated as normal Key drops, and have a small chance of being replaced by a Golden Key.