Baby is a major villain in Dragon Ball GT. He is a creation of Dr. Myuu who's goal is to destroy the Saiyan race in the name of the Tuffles.
Baby is a parasite that has the ability to possess bodies and lay eggs inside them.
In the English dub version of the Dragon Ball GT anime by Funimation Baby was voiced by Mike McFarland.
In an alternate English dub by Blue Water Baby was voiced by Adam Hunter.