To blow a big lead, a synonym of to choke. Typically used in the context of sports or video games. Often preceded by adjectives such as epic, huge, total, or major and punctuated by a well-timed bro or dude.
Another epic meltdown in Wii Golf from Kevin, bro.
Major meltdown dude. Classic Kevin move.
Gonna need a total meltdown from Kevin this round. He's up 4 strokes in Wii Golf but he has no mental toughness.