Isaac drops a large and more powerful bomb. This bomb has an increased blast radius of 3 squares in contrast to 2 squares like regular bombs.
- Mr. Mega will cause all your bombs to turn into the same kind of bomb Mr. Boom places.
- When Swallowed by Chub, C.H.A.D. or The Carrion Queen, it deals about one-third of a normal bombs damage to each part along with a bonus hit worth slightly more (than one instance). For those foes, it will always deal the former damage per segment like a regular bomb instead of the large explosion associated with the active (almost double normal bombs). Bob's Curse cannot apply poison when swallowed. It can otherwise (and is very effective when it catches multiple parts as with all other segmented foes regarding poison and explosives). The swallowed bomb's explosion cannot apply poison to nearby foes nor the glitch kill case with Best Friend. It can harm us (like a regular bomb) and will deal damage equivalent to The Necronomicon to those near.
- Against other segmented foes, it will deliver the large explosive damage (more than The Sun) and poison to each segment, though Scolex will take 5x damage for the explosive and poison if caught on the tail during its dive. It will only hit once when the tail comes out of the ground (and cannot hit the head). Poison applied when the tail comes out will end with a burrow. Its normal poison value (double The Virus) can be applied too (even at the same time as the special case), but it is unclear how.
- Bobby-Bomb - Causes Mr. Boom to home in on enemies.
- Bob's Curse - Poison effect also applies to bombs dropped by Mr. Boom.
- Placing Mr. Boom in a room, leaving, and returning to the room will cause Mr. Boom to turn into a normal bomb, but with the same increased blast radius.