Bob's Rotten Head 
Effects
- Upon use, Isaac holds a poison bomb which can be thrown in the cardinal directions and explodes on impact.
- (Removed in Repentance) The explosion deals a flat 50 + Isaac's tear damage and poisons affected enemies.
- (Added in Repentance) The explosion deals a flat 185 + Isaac's tear damage and leaves behind a gas cloud that poisons affected enemies. The poison cloud deals 5 damage.
- (Removed in Afterbirth) The poison deals 6 or 8 points of damage over time.
- (Added in Afterbirth) The poison deals 3 times Isaac's tear damage over time.
- (Added in Repentance) It will bounce off walls slightly before exploding on the floor.
- This item belongs to the (Added in Afterbirth)(Bob) Bob set. Collecting three items from this set will transform Isaac into Bob.
Notes
Interactions
- (Added in Afterbirth)(Bob's Bladder) Bob's Bladder /
Bob's Curse /
Bobby-Bomb / (Added in Afterbirth)
Bomber Boy / (Added in Afterbirth †)
Fast Bombs / (Added in Afterbirth)
Scatter Bombs /
Mr. Mega: No effect.
- (Added in Repentance)
Book of Virtues: Spawns wisps in the middle ring. The wisps shoot arcing green tears with decreased range, with a 7.5% chance of firing an explosive, poisonous tear.
- (Added in Afterbirth)
Car Battery: No effect.
- (Added in Afterbirth)
Continuum: Bob's Rotten Head can now travel through walls and appear out of the opposite wall, similar to a portal-type mechanic.
- (Removed in Repentance)
Cricket's Body/
The Parasite: no longer travels through the wall; instead he bounces off it, like with
Rubber Cement, and then travels for the rest of its duration and then explodes.
- (Added in Repentance) Causes two smaller tears to appear and then explode. Tears do not look like the normal head.
- (Added in Afterbirth / Removed in Repentance)
Explosivo / (Added in Afterbirth / Removed in Repentance)
Sticky Bombs: If Bob's Rotten Head sticks to an enemy (sometimes with Explosivo, always with Sticky Bombs), the explosion is delayed but will deal 110 damage.
- (Added in Repentance) No longer sticks to enemies.
- (Added in Repentance)
Flat Stone: Will cause Bob's Rotten Head to bounce once, exploding twice and leaving two gas clouds.
Rubber Cement: Causes the head to bounce off of rocks and walls.
Sacred Heart: Homing effect is applied.
Tiny Planet: When used, Bob's Rotten Head will orbit the player similar to a tear.
- (Added in Afterbirth †)
Trisagion: Explodes multiple times before reaching its target, dealing explosive damage and knockback to Isaac.
- Worm Trinkets: Bob's Rotten Head is affected by trinkets like (Hook Worm) Hook Worm and (Wiggle Worm) Wiggle Worm the same way tears are.