The Saxxy is a limited-edition melee weapon for all classes. It is a 75% Australium-plated statuette of Saxton Hale set into a small plinth. The Saxxy will function identically to the default melee weapon, except for the fact that when a player is killed, they will turn into a motionless Australium statue, in much the same way the Spy-cicle turns backstabbed corpses into ice statues. This is completely cosmetic.
The Saxxy is only given out to people who win the Saxxy Awards (Source Film Maker competition that is only held once per year), making it one of the rarest items in the game.