This spell turns the bones or bodies of dead creatures into undead skeletons or zombies that follow the character's spoken commands. The skeletons or zombies can follow the character, or can remain in an area and attack any creature (or just a specific type of creature) entering the place. The undead remain animated until they are destroyed. (A destroyed skeleton or zombie can't be animated again.)
Regardless of the type of undead, the character can't create more HD of undead than the character has caster levels with a single casting of animate dead.
The undead the character creates remain under the character's control indefinitely. No matter how many times the character uses this spell, however, the character can control only 2 HD worth of undead creatures per caster level. If the character exceeds this number, all the newly created creatures fall under the character's control, and any excess undead from previous castings become uncontrolled (the character chooses which creatures are released). If the character is a cleric, any undead the character might command by virtue of the character's power to command or rebuke undead do not count toward the limit.
Skeletons: A skeleton can be created only from a mostly intact corpse or skeleton. The corpse must have bones (so purple worm skeletons are not allowed). If a skeleton is made from a corpse, the flesh falls off the bones. The statistics for a skeleton depend on its size; they do not depend on what abilities the creature may have had while alive.
Zombies: A zombie can be created only from a mostly intact corpse. The creature must have a true anatomy (so gelatinous cube zombies are not allowed). The statistics for a zombie depend on its size, not on what abilities the creature may have had while alive.