Rohypnotist
Someone who tries to date rape someone using the drug rohypnol.
Guy1: did you see that guy over there try drop something in that girls drink?
Guy2: Really? - fucking rohypnotist!
Guy2: Really? - fucking rohypnotist!
Rohypnotist
One who uses Rohypnol to induce a 'trance'.
"Look into my eyes, not around my eyes, here, have a drink, you're under" said Ray the Evil Rohypnotist.