The guy’s name is Gregory McCalium.  He had a party and his neighbor called the cops with a noise complaint, who promptly showed up at Greg’s house and shut the party down.  Enraged, Greg decided the next morning to break into his neighbor’s house with a knife to settle the score.  This is his neighbor, 72 year old Frank Corti:

“You should see the other guy…”

What Greg didn’t know, was that his neighbor got all those trophies when he was this guy:

He was a junior boxing champion haha.  Ol’ Greg didn’t see that shit coming. Turns out Frank Corti still has quite a bit of fight in him, and upon seeing his retarded neighbor, proceeded to pound the crap out of Gregory’s face until he looked like someone punched him with a vehicle. 
Full story here.