S03E04 - XXX: Jack and the Zombies
Synopsis
Aku resolves to do something about The Samurai once and for all and lures him into a cemetery. Then the wizard unleashes hordes of the undead and one of the creatures manages to possess Jack's sword and deliver it to Aku. Armed with the sword and his own shape-shifting powers, Aku runs Jack ragged and then captures him and tries to kill him with the sword...which Jack finally remembers can't be used by the evil to harm the innocent. With the sword incapable of harming him, Jack regains his weapon and drives Aku away.