He regularly asks people about their astrology
He's a Pisces and thinks his inherent intimidation of you is totally rational because you're a Scorpio. He has an app on his phone to keep track of the phases of the moon and has mentioned more than once that it's his "month." If you really want to ruin his day tell him his ruling planet is Pluto and that astrology is a pseudo-science made up by Bob Ross on hallucinogenics.