Mimics a random shooter familiar's shots each time it fires.
- Brother Bobby (regular tears)
- Sister Maggy (blood tears)
- Little Gish (slowing tar shots)
- Little Steve (homing tears)
- Demon Baby (copies Isaac's current tear effect)
- Ghost Baby (spectral tears, copies Isaac's current tear effect)
- Harlequin Baby (V-shot)
- Sometimes when entering a room, Rainbow Baby will turn into Brother Bobby.
- If the player has Isaac's Head, Rainbow Baby will turn into Sister Maggy, even if the player already has that item.
- A rainbow baby is a baby that is born following a miscarriage or still birth.
- The art for it shows big, gleaming eyes; but the familiar itself has X's for the eyes.
PC: CF8M YB0Q (Adjacent to spawn)
GAY9 7QRQ (Second floor treasure room)
7H71-WRLV (Adjacent to spawn)
QJ3L NRKA (Also has skeleton key with marked rock by it on first floor)