Ragged sea hare (Bursatella leachii).   An unusual type of sea slug, about as large as a fist.

(Critter Corner, St. Vincent, British West Indies)

mollusc; gastropod; sea slug; sea hare; ragged sea hare; Mollusca; Gastropoda; Anaspidea; Aplysiidae; Bursatella leachii, Caribbean