A Right Number Six
A Right Number Six is someone who's full of themselves and can't shut up, especially when they're not actually good at what they're doing.
"You're lucky I didn't kick your ass!", said by a guy who got tackled by a toddler.
"I could've beaten you if I wanted to!", yelled at someone who was already out of breath.
"I'm the best, and you're the worst!", said by a guy who didn't even show up to the match.