Onchidiopsis corys is a species of small sea snail with a transparent internal shell, a marine gastropod mollusk in the family Velutinidae.

The thin dorsal surface (notaeum) is smooth on top and on the sides, but wrinkled and vesiculate elsewhere.

This shell covers the top and the sides of a large visceral hump, suggesting in its form a Homeric helmet (Greek : korys), hence the name of the epithet corys.

This hump is a smooth dome of purplish-yellow visceral mass, mainly consisting of the glands of the genital system.

The marginal teeth are formed like arched claws, curving upward, backward and slightly outward.