Brachiopod: a marine animal, similar to a mollusk.  The brachiopods has a pair of tentacled arms used to capture food. 

Brachiopods are hinged at the rear end.  The front opens when the creature is hungry and closes when it needs protection.  In extremely dangerous situations, the brachiopod may not close for protection.  It may just pull out a pistol and start shooting.  As I said, this is rare.  So, rare that no one has ever seen it happen.  Ever.  But, facts alone will not keep me from believing.

The word “brachiopod” is formed from the Greek words βραχίων (brakhíon), arm and πούς (pous), foot.