Bleach - Season 1 Episode 6 -

Rukia purchases a temporary soul at Urahara’s store for Ichigo to use when she is not around and he needs to fight a Hollow. What Rukia does not realize is that what she purchased isn’t a normal temporary soul; it is a modified soul with special powers created by the Soul Society. When this modified soul takes Ichigo’s place it decides to have a little fun in Ichigo’s body and refuses to give it back to Ichigo.