UPDATED - Dec. 2010: Goad's Grinder Shrine - Removed information, players won't actually die if they lose in this arena, that function was removed. The player who dies must be (10HP or > more) than the player who kills them in order to teleport the winner to the shrine.
You must visit The Goad with a friend (or foe). As mentioned in this NPCs description, The Goad gets off by witnessing a kill.
Two people must fight to the death, in the presence of The Goad. The winner of the duel will be teleported to the shrine.
The Goad's arena works much in the same way that the Tos arena does, with the commands "champion", "challenge", etc.
There is NO renege option. If you log you will die, if you fall off the platform you will also die.
Good luck!