Bleach Episode 06 - “Fight to the Death! Ichigo vs. Ichigo”

In order for Ichigo to transform into a Soul Reaper when Rukia is not around, she purchases some soul candy from the Urahara Shop for him. However, the candy is actually a modified soul, an artificial warrior from Soul Society created to destroy hollows. Once inside Ichigo’s body the modified soul goes on a rampage, ruining Ichigo’s social image.