Yuku Tokoro(1998)

Koizumi, a young man in high school with an alcoholic father and a neurotic mother, lives alone and spends his days living an ephemeral and hedonistic life. One day, he has a stomach cramp and asks for help from his classmate Minato, who confesses that he is gay and has feelings for Minato, and starts following him around.

Koizumi, knowing that Minato's right half of his body is handicapped by polio, bullies Minato to make him feel inferior because of his disability, while at the same time jumping into the river to save an abandoned kitten at Minato's request. The two develop a twisted relationship that cannot be described as friendship or love.

(Source: Wikipedia Japan, translated)