Schrödinger's douchebag

noun1

1. •
   (disapproving, vulgar) A person who makes offensive or inflammatory remarks and characterizes these statements as either sincere or joking based on the reactions of others.

   • "Schrödinger’s douchebag" [i]s someone who makes an unacceptable remark and then waits to see the reaction before declaring retrospectively whether they meant it for real or were "just joking". — 2016