Once only a puppet, Puppet King had a human soul put into him, which somehow triggered his need to be a "real" puppet master. Switching Robin, Cyborg and Beast Boy's souls while they slept, the three boys became walking zombies, with only one intention: to get Starfire and Raven to join them.
The Puppet King was pulling the Titan's strings, smashing and twisting everything their path in order to get to the girls--but to no avail. The girls avoided the Puppet King and the zombie Titans, even with their minds and bodies switched. The control that the Puppet King used to steal the souls was destroyed, and, in effect, his soul disappeared as well.