InuYasha Episode 164: Possessed by a Parasite: Shippo, Our Worst Enemy
Episode 164 of 167 of InuYasha, aired August 30, 2004, 24 minutes. Available with English subtitles and dub where released.
Episode summary
A parasite demon infects Shippo, causing him to attack his friends, but Inuyasha seems to be the Shippo's real target.