- Spits a diagonal stream of shots, propelling her across the room while she bounces off walls.
- Twirls towards the player, firing shots in all directions.
- Jumps, firing two rings of blood shots in all directions and leaving behind a small pool of red creep.
- One of the rings of shots travel outwards slowly while the second one travels faster but has wider spaces between each projectile.
- Upon death, she releases a ring of 10 small tears.
When not attacking, Baby Plum slowly hovers towards the player.
- Baby Plum, like several other bosses in Antibirth, is based on a group of common monsters encountered on various floors. Baby Plum is based on flies, like Suckers, Red Boom Flies, and Level 2 Flies.
- Baby Plum is the only boss introduced in Antibirth that only appears in Rebirth floors and not on any Antibirth floor.