Mirror Lake (Season 2, Episode 5)

Mirror Lake is the fifth episode of the second season of the Mushishi anime series.

Summary
Ginko encounters a young woman being followed by a mysterious, watery creature. The woman becomes weak, and her family believes it to be lovesickness. Ginko reveals the truth of the mushi attached to her, but the woman must decide whether to give up her body to the mushi, or to dispel it and continue living.