The Ban Hammer is a selectable weapon available to the host of the world, and is used to kick other players from the game.
When there is more than one player in a server, holding the ban hammer doubles your movement speed. To kick a player from a game, the host must run up to the offending player and press the Left Trigger to kick them. Upon being kicked, a rainbow particle effect appears in place of the avatar, and a message will appear to the player that they were kicked. Another message will appear to the clients, informing them that the offending player has been kicked. However, you can freeze everyone in the server by using the Right Trigger, which makes it easier to kick the offending player, as they are frozen and cannot run away.
If you are kicked out of a game, you are directed back to the main menu and a message appears on the screen containing crude humor informing you to stop griefing (if this is the reason you were banned) but it does not prevent the kicked player from re-entering the world again.
On the opposite side on the head of the Ban Hammer, the side the player cannot see, the words "U MAD BRO?" are written.
This weapon was released on August 10, 2011, in the 1.09 Patch.