Definition of "lobsterman"
(fiction) A fictional alien or monster that looks like a lobster/human hybrid.
Quotations
As the show progressed during its second season, the Cold War villains disappeared and Voyage settled into an entertaining, kid-friendly “monster of the week” formula, with the Seaview crew encountering aquatic beasts, ghosts, aliens, dinosaurs, an evil brain, a lobsterman, an ancient alchemist, and even a werewolf.
2018, Michael Eury, “Irwin Allen: Voyage to the Bottom of...the Barrel??”, in RetroFan, volume 3, page 33