We have a guy (not a teenageer) that does this crap all the time.
One time he loaded the Squat rack with a little over 600, strictly this guy may be able to do 315. Well his first set without a warmup was with 405, not even 1/4 reps squats second set went up 495, again not even 1/4 reps. then jumps up to a little over 600, he starts to get load and smacks himself, jumps under the bar starts to go down, he got to 1/4 of the way and could not come up. thats when everone watching this idiot walks away. as everyone walks away we hear the weights slam on the floor, he was lucky he didn't breaks his back. but wait the idiot is not done, he goes to the Hack Squat loads (4) 100lb plates on each side, and does 1/4 squats. that is where everyone thaught we would see him kill himself. this guy does this with every excerise, his curls look more like Power cleans.
can't wait to see him crash and burn, hopefully a broken leg or something like that.
funny as hell!!