I live in Washington state and these "Moon snails" are pretty crazy.
Wikipedia wrote:The northern moon snail, Lunatia heros, is a species of large sea snail, a predatory marine gastropod mollusk.
It is found rather uncommonly intertidally, but is much more commonly subtidally. This species, like all moon snails, feeds voraciously on clams and other snails.
This is a western Atlantic species, which occurs from the Gulf of St. Lawrence to Delaware.
Northern moon snails are found on mud and sand substrates at depths of up to 364 m (1,200 ft).
The shell of this species is globular and can, under the right conditions, grow as large as 125 mm (7 inches) in maximum dimension.
The operculum is large, ear-shaped in outline, and is corneus and somewhat transparent. On beaches where the shell of this species washed up commonly, the operculum will usually also be found washed up in the drift line.
Moon snail predation
Evidence of northern moon snail predation is usually much easier to find than the snails themselves:
The powerful foot enables this gastropod to plow under the sand in search of other mollusks. Upon finding one, it "drills" a hole into the shell with its radula, releases digestive enzymes, and sucks out the somewhat predigested contents.
When empty shells of clams and snails, including other moon snails, are seen to have a neat "countersunk" hole drilled in them, this is evidence of predation by a moon snail.
These aren't my pictures, I found them on Google
This is one of their egg capsules.