When someone suddenly passes out randomly while doing something, usually in a abrupt and random matter that is usually dangerous and potentially life threatening.
*everyone watching movie, laughing*
Friend 1 - "Hey Jason, did you see that?"
Jason - ZZzzZZzz *snore*
Everyone - "WTF, he was just awake a second ago?!"
Friend 1 - "Fuck, he must've narcolepsied again. That shit is going to happen when he's driving one day and he's going to crash and die"