The bearmonkey is a euphemism for a hangover. One usually receives a visit from the bearmonkey after a long night of drinking way too much
alcohol.
The bearmonkey is a creature that sneaks into your room at night and
slaps you around, fucks up your hair, presses on your eyeballs, shits in your mouth and steals all of your money.
The
day after a visit from the bearmonkey, one usually has bloodshot
eyes, feels like crap and looks like crap, has terrible dry mouth, stinky breath and can't figure out where all the money in his wallet went.