Crustacean Anatomy – The character has the form and/or characteristics of a crustacean. Crustaceans include crabs, lobsters, crayfish, shrimp, krill and barnacles.
Superman (DC) fights a lobster robot in Action Comics #758.
There is a crustacean named Crustacean in the Savage Dragon Universe.
Mudbug (Marvel) is a crayfish hero in the works (Wolverine & the X-Men V1 #20).
Titano (Marvel) is a giant crab that appears in Tales to Astonish V1 #10.
The Dungeons and Dragons universe has two crustaceans including Chull (D&D 4th Edition – Monster Manual 1), and Craud (D&D 4th Edition – Monster Manual 3).
The World of Warcraft has the Makrura that looks like a crab (World of Warcraft Monster Guide).
Cave Fisher – TSR 2140A Monstrous Manual
Crabman – TSR 2140A Monstrous Manual
Giant Lobster – Tales to Astonish V1 #1
Keel Crusher – Creature Collection II. Dark Menagerie
Sand Hulk – Creature Collection III. Savage Bestiary
Sea Hermit – TSR 2173 Monstrous Compendium Annual Volume 4
Siege Crab – D&D 3.5 – Monster Manual III
Skiver – Creature Collection II. Dark Menagerie