|??? (Blue Baby)|
| Floors of
| Base Health||2000|
|Unlocked By||Beat Isaac with The Polaroid|
|Items Dropped||Boss Chest|
Blue Baby goes through three stages depending on his health. During each of these stages, he will shoot a very small amount of tears in a wave pattern at Isaac which have a chance to be homing. His stages are as follows:
- Blue Baby fires lines of tears in an asterisk pattern. He fires lines of tears in a spiraling asterisk pattern and also fires a single tear at Isaac.
- Blue Baby now has Eternal Flies orbiting him. He shoots one or two tears at Isaac and can also fire 4 or 8 homing tears in an asterisk pattern. He can also fire lines of tears in a spiraling asterisk pattern and spawns many types of flies to orbit him.
- Blue Baby will spawn many more flies to orbit him, the flies being sent to attack Isaac when he teleports. When he teleports, he teleports to where Isaac is moving or on him if he isn't moving. He will also shoot one or two tears at Isaac or fire lines of tears in a spiraling asterisk pattern.