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.