Banquet Biters are unique weapons in Xenoblade Chronicles. They are biters wielded by Riki, and can be obtained from numerous high-level enemies. They are not otherwise available. As a Unique Weapon, it is similar to Melia's High Entia Soul, giving the player three free gems with which to improve status effects.
Banquet Biters have the ability to damage Mechon although it is not explicitly indicated whether this weapon can damage Mechon or is built from Mechonis parts like for usual "Anti-Mechon" or "Machina" weapons series.
Sources
Enemy drops
Note: For any enemies listed with a 0% drop rate, the item can only be obtained using Yoink!