The Overwatch is a weird community, but is incredibly fun and (usually) welcoming. While there have been always players goofing off and forgetting about the match entirely, very rarely does a hammer on hammer beatdown not only occur, but disrupt most of the end portion of the game.
On April 23, near the end of an Overwatch match, two Torbjörns decided to duke it out near the end of the match, with the winner being allowed to finish their objectives. Thus it began, as two blacksmiths started to hack at each other with their hammers. While they fought like roaming gladiators, the rest of the team stood there, simply watching and spamming their voice lines during the action. Sadly for the OP, the other team won, and his team displayed absolute sportsmanship and hurled themselves off the edge of the map, letting them take the win.
In terms of unique ways to end a match, if not the most awe-inspiring, this is definitely one of the more memorable ways to do so. Hopefully, Overwatch 2 can put a mode in the game like this, as it'd be a fun way to mess around with friends when you're getting tired of the main match.