As bizarre as this story is, I have no problem with Mopee--on a conceptual level. Superheroes, particularly in the Silver Age, had strange impish side characters. That's just how it was.
Superman had Mxysptlk, Batman had Bat-Mite, J'onn had Zook, Aquaman had Qwsp, Wonder Woman had Shaggy, the Flash has Mopee.