clionidae
A small floating sea slug, clionidae or "sea angels" are ferocious little predators that hunt the "sea butterfly," Limacina helicina.
When tasty sea butterflies get close, sea angels shoot out tentacles, grasp the prey with hooks and extract the body completely out of the shell to swallow it whole. Incidentally, this is also how my brother Benny feeds.
A clione shows a limacina what's what.
Two clionidae try to pretend that they are not mucus hungry snail murderers.