Scare Wizard
(n.) An extrordinarily creepy old man who at first glace seems completely harmless, but minutes into a conversation it is easy to realize that he is whacked out of his gourd. Telltale signs include talking about past relationships which he would "break his kneecaps" to have back; talking about obscure areas of science that have to do with energy transfer and telling everything about a person by their microfacial movements; and especially speaking in a language that they have themselves made up and asking if you recognize what they are saying.
Holy shit, that fucking scare wizard would't stop talking about his garden where he grows human emotions in soil with mustard seeds, what a whackjob.