Most sea slugs use their raspy tongues to feed on prey that is attached to the seafloor. Instead, Bathydevius caudactylus works a bit more like a Venus fly trap. It uses a cavernous hood to trap crustaceans. Some other unrelated deep-sea species–including some jellyfish, tunicates, and anemones–use this feeding strategy.

A "remarkable" new sea slug nicknamed the “mystery mollusk” has been discovered swimming deep in the ocean's "midnight" zone. The species has "unique" adaptations for life in the pitch-black depths including a large gelatinous hood to trap prey,