Battlehorn: A battlehorn is a double weapon that consists of two large horns affixed together, facing in opposite directions. You can fight with it as if fighting with two weapons, but if you do, you incur all the normal attack penalties associated with fighting with two weapons, just as if you were using a one-handed weapon and a light weapon
(see Two-Weapon Fighting, page 160 of the Player’s Handbook). A creature wielding a battlehorn in one hand can’t use it as a double weapon—only one end of the weapon can be used in any given round. If you use a ready action to set a battlehorn against a charge, you deal double damage if you score a hit against a charging character.
Exotic Two-Handed Melee Weapon
Cost: 50 gp
Dmg (S) 1d6/1d6 Dmg (M) 1d8/1d8 Dmg (L) 2d6/2d6
Critical: x3
Range Increment:
Weight: 10 lb
Damage Type:Piercing
Source: Sandstorm