Pet Shop of Horrors

Pet Shop of Horrors is a manga created by Matsuri Aiko which was also adapted as an OVA. Inside of Chinatown there is a pet shop with an exotic selection. The owner, Count D, can find amy an unusual creature tailor picked for the customer, but every purchase comes with a contract that must be followed.

Medusa
A washed up actor and collector of lizards enters the pet shop looking for a new pet lizard to get his mind off his girlfriend recently breaking up with him. Count D suggests the medusa to him. While once used as living weapons, this medusa is both willingly blindfolded and docile. The actor takes to her instantly and agrees to purchase her. While she does raise his spirits, he is brought down again when he is rejected for a part in an upcoming film. He decides to take his own life, and after confessing his love for the medusa he removes her blindfold and looks into her eyes. He dies instantly, and as the medusa loved him as well, she looks into her reflection and dies as well.

Mermaid
After losing his wife on the day of their marrage, a publicity manager visits the pet shop to find out what pet his wife had ordered shortly before her death. He is shown a mermaid that bears a striking resemblance to his late wife, and the Count mentions that he found the mermaid on the same day as his wife's death. After signing a contract which required him to care, and feed, the mermaid he takes her home and puts her in his swimming pool. Over several days he becomes more and more convinced that the mermaid is his late wife, and that he is in love with her. The police show up to find the manager's body half eaten and have no choice but to destroy the mermaid.