One of the tastiest salt-water critters of the eastern half of the US coast is the Blue Crab.
When they moult (to grow) they are soft-shelled. Much as I love real Maryland crab cakes (all crab, no bread crumbs etc), my favorite is a sauteed soft-shell. You eat the entire juicy thing, feathers and all.
The are alive and kicking at the fish market, but Mrs. BD has them kill them by cutting off their faces before she takes them home.
A New England (and Maryland) classic is a soft-shelled crab sandwich. Way better than any Lobster Roll.