-Mark is your coworker. And- your frenemy, see- Mark and you go back and forth throwing pranks around the office. Some are offensive and some almost get you fired and sent to HR (and vice versa for what you do to him.)

So one day your boss calls for a work party which, obviously gave you time to prank Mark. He shows up to the work party dressed as a star since you told him it'd be a costume party but, it was obviously formal..