Piliscus commodus

Piliscus commodus is a species of small sea snail with a transparent internal shell, a marine gastropod mollusk in the family Velutinidae. Because the shell is mostly internal, the snail resembles a sea slug in general appearance.

Description
The maximum recorded (shell?) length is 28 mm.

Habitat
The minimum recorded depth for this species is 40 m; maximum recorded depth is 325 m.