Takahashi Rumiko Gekijou Ningyo no Mori EP12 - Mermaid's Scar (Part I)

Yuta and Mana encountera boy called Masato who is traveling from Tokyo to live with his mother. One night two years later, Masato stabs his mother in the chest, then cleans up the murder scene. However, the next morning when the housekeeper Yukie arrives, Masato's mother is alive again. At a nearby seaside a nearby construction site where Yuta and Mana are working, Yuta learns about a mysterious body that washed ashore and how that after Masato's mother died in a boat accident, she came back to life. Later, Masato's mother notices that her chest wound isn't healing and attacks Masato demanding mermaid flesh, but the boy is saved by Yuta. Masato gives Yukie a piece of mermaid flesh, hoping to make her immortal, but she becomes a Deformed instead and attacks Masato and his mother. Yuta arrives in time to kill the monster, but then realizes that it was Yukie. Mana escapes to safety with Masato who leads her to his hiding place. Meanwhile, Masato's mother tells Yuta that the immortal Masato gave her mermaid flesh after a Pacific War bombing raid, making her essentially his immortal captive mother. She ran away, but he found her again from after news of the boat accident. She finally dies from wounds inflicted by the Deformed. In his hideout, Masato suddenly tasers Mana and prepares to kill Yuta.