InuYasha Episode 100: The Truth Behind the Nightmare: Battle in the Forest of Sorrow
Episode 100 of 167 of InuYasha, aired February 10, 2003, 24 minutes. Available with English subtitles and dub where released.
Episode summary
While travelling, Inuyasha smells a familiar scent; it's the moth demon leader. As they battle the leader, everyone except Inuyasha gets trapped in a cocoon, where they have nightmares about their worst fears.