It's a baseball bat with stunning powers, literally. You whack a baseball into an opponent too "slow, drunk" or "Australian enough" to get out the way and it stuns the sucker.
As per the official words of the Valve propaganda machine 'The Sandman' is a "highly collectible bat that smacks baseballs at the other team, stunning the living crap outta anybody dumb, slow, drunk, mute or Australian enough to get in the way."
The further a target is away the stronger the impact of the stun so major league jerks who know how to hit a ball with a glorified stick should be thrilled. "The farther the ball flies before ricocheting offa some chucklehead's skull, the longer he's gonna be stunned."
There's just one problem... you can't double jump while holding the bat - just like it real life! Oh wait you can't jump 'again' whilst in the air in real life. Well, that sucks.
The update goes live this upcoming Tuesday, February 24th.