Zombies. Unlike skeletons, which are merely the desiccated framework of a creature's form, a zombie is an animated corpse. Most sages maintain that the zombie, like the skeleton, is a mindless slave, but this is clearly not the whole story. Those who have experimented with animated cadavers (most notably Kazerabet in the Art of Necromancy) have revealed that most zombies remember some facts about their former lives, depending upon how quickly they were animated after their deaths. Clearly, the animated corpses of the long dead, whose worm-eaten brains have been filled with cobwebs and rats' nests, will have little or no recollection of their former selves (in this case, they conform most closely to the stereotypical description of the zombie in the MM). However, those zombies who are raised up almost immediately after their deaths can be ordered to recall facts about their life to their current masters. Despite this interesting feature, however, a zombie is little better than a skeleton in terms of its ability to act independently and of its own initiative.
The common zombie can be brought to unlife temporarily by a necromancer at 5th level (with bone dance) or permanently at 9th level (with animate dead). A priest can create permanent zombies at 5th level with animate dead. Note that the clerical as well as the wizard versions of animate dead can raise animal and monster as well as common zombies.