The World of Kanako: This would be an unhinged fever dream no matter who is picked. I'd like to propose Ogata for shock value in a particular scene, but I think either Kanako or the main character detective overall work better
The entire Saw franchise: Jigsaw
SLC Punk: Heroin Bob
Tokyo Gore Police: Key Man
Hook: Everyone in the real world is human, everyone but hook in Neverland is a muppet, and Robin Williams starts human but by the end is a muppet
Les Mis: Javert
X: The old woman
Swiss Army Man: Daniel Radcliffe or Paul Dani could work here but I prefer the dead body
Any zombie movie but people start human and turn to muppets when bit. I nominate - - - Train to Busan
This is going to get me put on a watchlist...
Too real
Yeah of all the things I listed this one is the most deranged