Triple Dagger (3.5e Equipment)
From D&D Wiki
The triple-dagger was a weapon used by European fencers. In its closed position this weapon appeared to be a plain dagger, but when a release catch was pressed, two side blades pushed out from the central blade to form a sort of trident. In this form the weapon was rather handy in parrying rapiers and other thrusting-type weapons.
The weapon is built and designed for breaking melee weapons. For game purposes, treat this weapon as a large two-handed weapon when determining modifiers to opposed sunder checks. Due to the weight and design, this weapon is considered an exotic weapon. The damage during sunder is bludgeon when the sides are released otherwise it does piercing damage like a regular dagger.