This is such a great idea I can't believe this is the first I'm hearing of it: it's a Team Fortress 2 mod where one team plays as a team, and the other team plays as Saxton Hale.
That's about the gist of it. The Red Team plays as normal, the Blue "Team" is a lone wolf, controlling the mightiest Australian of them all in a bare-knuckled brawl to the death.
The Reds get all their regular weapons and gear. Saxton? He gets a hat, his fists, and a health gauge that gets bigger the more Reds there are trying to take him down. It hardly seems fair. Actually, looking at this clip below, it's not fair.
[thanks Edward!]