Glyceridae is a family of polychaete worms. They are commonly referred to as beak-thrower worms or bloodworms. They are bright red, segmented, aquatic worms. The proboscis worm Glycera is sometimes called bloodworm. The Glyceridae are ferocious epi- and infaunal polychaetes that prey upon small invertebrates. They are errant burrowers that build galleries of interconnected tubes to aid in catching their prey.