Ningyo no Kizu (1993)

Mermaid's Scar

As the immortal Yuuta and Mana continue their journey across Japan, they encounter a young boy named Masato traveling alone on a train. When Masato reunites with his mother, Yuuta and Mana squeamishly witness her assault him with a pair of scissors. Following their investigation, Yuuta and Mana discover that the young boy is not what he seems. The curse of the mermaid's flesh has reared its ugly head once again. [Written by MAL Rewrite]