Isaac's bombs create ghosts when they explode, which rapidly chase and deal contact damage to enemies.
The ghost deals contact damage equal to half of Isaac's damage per tick (2× Isaac's damage per second).
After 10 seconds, the ghost explodes, dealing 7 damage to nearby enemies up to 3 times and destroying nearby projectiles. Isaac does not take damage from the explosion.
If there are no enemies in the room, the ghost follows Isaac. However, it cannot follow Isaac between rooms.
Dr. Fetus: Has a chance to shoot a Ghost Bomb that also has spectral properties and can travel through objects.
Scatter Bombs: Split bombs create ghosts that instantly launch themselves at enemies and explode, similar to Purgatory. They each deal 2× Isaac's damage, up to 4 times.
Mr. Mega: Ghosts appear larger and do extra damage only upon exploding.
Defeating Delirium as most tainted characters will unlock their gameplay characteristic. Interestingly, Tainted Lost's passive ability to reroll low quality items (Sacred Orb) is unlocked through defeating The Beast instead.
This item may be a reference to "Super Ghost Kamikaze Attack" from Dragon Ball Z.
Bombs.
Dr. Fetus: Has a chance to shoot a Ghost Bomb that also has spectral properties and can travel through objects.
Scatter Bombs: Split bombs create ghosts that instantly launch themselves at enemies and explode, similar to 
Purgatory. They each deal 2× Isaac's damage, up to 4 times.
Mr. Mega: Ghosts appear larger and do extra damage only upon exploding.
Doctor's Remote/
Epic Fetus: No effect.
Ipecac: The ghosts get only +1 flat damage from Ipecac, not the expected +20.
Libra: The ghosts ignore damage modification from Libra, both positive and negative: the actual unbalanced damage value is used.
Delirium as most tainted characters will unlock their gameplay characteristic. Interestingly, Tainted Lost's passive ability to reroll low quality items (
Sacred Orb) is unlocked through defeating 
The Beast instead.
Anarchist Cookbook
Blood Bombs
Bob's Curse
Bob's Rotten Head
Bobby-Bomb
Bomber Boy
Boom!
Brimstone Bombs
Butt Bombs
Curse of the Tower
Fast Bombs
Ghost Bombs
Glitter Bombs
Hot Bombs
Kamikaze!
Mama Mega!
Mr. Boom
Nancy Bombs
Number Two
Pyro
Remote Detonator
Rocket in a Jar
Sad Bombs
Sticky Bombs
