Homunculus

Homunculus is a monster that has a small range of movement because it is attached to the wall or an Obstacle. Given enough time it will detach, shooting 6 blood shots in all directions and chasing quickly after Isaac. It leaves a small amount of Red Creep when it dies while attached or if it detaches itself.

Begotten
Begotten acts like Homunculus but doesn't leave Red Creep when it dies. When it detaches from the wall or Obstacle, it fires 6 blood shots in all directions, turns the room dark and becomes invisible. However, it temporarily becomes visible if it takes damage.

Trivia

 * A homunculus is a very small human or humanoid creature.
 * Similar to Frowning Gapers and Nulls, Homunculi and Begottens are seen in a sleep-like state at the start of a room before they immediately open their eyes and attempt to pursue the player.
 * Begottens are the only non-boss enemies that can cast a "curse of darkness" effect.
 * Homunculi will still leave behind creep if re-rolled with.