Halystina umberlee is a species of very small deep-water sea snail, a marine gastropod mollusc in the family Seguenziidae.

[1] It was named after Umberlee, a fictional goddess from the Faerûnian pantheon of the Forgotten Realms campaign setting for the Dungeons & Dragons fantasy role-playing game.

[1] Its bulbous protoconch consists of a single whorl with a pitted surface, and the protoconch-teleoconch transition is marked by a thin line.

The axial threads form an overall continuous sigmoid pattern along the shell's longitudinal axis, and the spiral sculpture becomes gradually weaker toward the basal region of last whorl.

[1] This marine species occurs off southeastern Brazil, from Espírito Santo to Rio de Janeiro, at 950–1550 m depths.