Probably the funniest BnHA headcanon I've ever come up with and ever could come up with is the one where everyone thinks Goncharov is a real pre-Quirk movie that was lost in the Quirk wars....except for Chisaki, who tried to hunt it down for a literature assignment or something and is now convinced it was a mass hallucination with the same strength (and connotation) of Shouto thinking Deku's All Might's lovechild.
(Important Tumblr tags: this man is autistic as FUCK and he chooses the WEIRDEST hills to die on, literally no one believes him. not even hari)