Butt Penny 
Effects
- Upon picking up a coin, Isaac farts, knocking back nearby enemies (Added in Repentance) and projectiles.
- (Removed in Repentance) The fart does not deal any damage or inflict poison.
- (Added in Repentance) The fart inflicts poison.
- Greatly increases the chance of coins dropping from poops.
Synergies
Interactions
- (Tainted Keeper) Tainted Keeper: All coins dropped from enemies trigger the effect, helping in defending Keeper or damaging nearby enemies, though the knockback could make collecting coins more difficult were there a lot of them dropped close to each other.
Gigante Bean: The size of the fart is drastically increased.
Swallowed Penny: Pennies dropped can be used either defensively to deflect projectiles, (Added in Repentance) or offensively to poison.
Mysterious Candy: Allows Isaac to slowly farm coins over time.