Your buddy that will succumb to only the slightest amount of peer pressure due to the overwhelming belief in the mantra YOLO (You Only Live Once). This buddy usually gets into very precarious situations due to overconfidence that commonly end in negative results. Yolo Bros behave much like Gremlins; only it's booze that will entice them after midnight, as apposed to food in the case of Gremlins.
Professor: What happened to Skindogg after I left the bar last night?
Knuts: Oh man, he turned into a Yolo Bro right before last call and ended up pissing his bed again.