Belly Jelly is a passive item added in The Binding of Isaac: Repentance.
- Enemies that touch Isaac will bounce off him and propel in the opposite direction. If they hit an obstacle or wall while bouncing, they will take damage.
- If an enemy bounces into another enemy, the second enemy will also take damage.
- When an enemy bounces off of Isaac, there's a 50% chance that Isaac won't receive contact damage.
- Additionally grants a 50% chance for projectiles to bounce off of Isaac without taking damage.
- The damage enemies receive when they get bounced into a wall or an obstacle is equal to
8 + 2 * floor.
- The same damage value applies when an enemy gets bounced into by another enemy.
- Enemies that don't deal contact damage cannot be bounced off.
- Bounced off projectiles deal a flat damage that doesn't scale with the current floor or Isaac's stats. This damage is usually 6, but can slightly vary depending on the enemy that shot the projectile.
- Lasers cannot be bounced off.
- The bouncing effect also works against Fire Places and spiked enemies such as Poky, Slide, and Grudge, granting a chance to avoid unintentional damage.
- Isaac can also bounce off Fly Bombs spawned by Blasters and even deny damage from their explosion.
- Bombs and Troll Bombs cannot be bounced off.
- This item can be considered a direct upgrade to Infamy, as the chances to deny projectile damage are equal, but Belly Jelly additionally works with contact damage, unlike Infamy.
- Aries: Retains the chance to bounce enemies while preventing damage simultaneously.
- Book of Shadows / Unicorn Stump: Can be used as a powerful offensive item since Isaac can still bounce off enemies while invincible.
- Cone Head / Host Hat / Infamy: Offers an additional chance to negate damage.
- Gnawed Leaf: The bouncing effect works while Isaac is invincible.
- Panic Button: The active item will still be activated if Belly Jelly blocks damage.
- Serpent's Kiss: Allows Isaac to bounce enemies and poison them at the same time, with a decent chance to get a lot more health back in the form of Black Hearts than originally spent.
- Belly Jelly is just the brand of jelly beans Jelly Belly®, but the words are flipped. Given the game's theme, this also might be a reference to the jelly spread on the belly before an ultrasound.
- The costume given by this item is identical to Bucket of Lard and Binge Eater.
PC CZBW A9HJ (Treasure Room adjacent to spawn)