The stereotypical spiral seashell, bumpy on the large end, tapering
to smooth opening on the narrow side, is an idealized knobbed
whelk.
Whelks are clam-eating salt-water gastropods -- though they only
eat one clam every month or so. The whelk's small proboscis contains a
raspy radula, which is festooned with even smaller denticles. The
whelk can use the radula to bore holes in clamshells, or it can force
the clamshell open with its large foot, wedging in the edge of its own
shell to keep the clamshell open. Some whelk, notably the Rogue Rapa
whelk, are large enough to engulf clams whole, at which point they open
of their own accord and expose their fleshy insides to the predator.
When cargo ships dump ballast, larval whelks can get
transplanted from one ecosystem to another. This can cause devastation
to local populations of oysters, clams, and mussels.
The knobbed whelk is the official state shell of New Jersey,
USA. However, despite whelks being found on beaches all over New
Jersey, it's not part of the local cuisine there. Whelks are more likely
to be found in Chinese, Korean, or Italian cookbooks.