What does John do?

New levels of degeneracy

John couldn't really stop himself as he pulled out of the sentient rubber doll that just moments ago had been his flesh and blood sister.

She wasn't dead, he wasn't that much of a monster but she was conveniently drowning in ecstasy. Every touch was orgasmic every second she spent in this form of brain became more malleable and moulded to sexual pleasure. He dropped on the floor of the shower, marvelling at how he had stretched out and soaked her sex with his seed. It was time to see what else he could do.

Snap

Melanie wasn't there anymore, he'd sent her somewhere where she could get more sexual experience by the time he went to get her she probably have been used by every college boy in town and he'd have a completely pliant toy.

He walked out of the bathroom not bothering to put on clothing, he wandered upstairs wondering what his new transformations had done to the rest of his family. First he would visit Erika then you would see what he could do with his parents. His dad would make an excellent dildo.