Oonopidae, also known as goblin spiders, is a family of spiders consisting of over 1,600 described species in about 113 genera worldwide, with total species diversity estimated at 2000 to 2500 species. The type genus of the family is Oonops Keyserling, 1835.

Unicorn ("one horn", in Latin) is a genus of goblin spiders from South America, containing seven species that occur predominantly in high elevation, semi-desert regions of Bolivia, Chile, and Argentina. Individuals are relatively large for goblin spiders, measuring up to 3.0 mm (0.12 in) in body length. The genus name refers to a characteristic pointed projection between the eyes and jaws of males. In at least one species, broken-off tips of the male pedipalps have been found within the genitalia of females, postulated as a means of sperm competition. Unicorn possesses several traits that suggest it is a relatively "primitive" member of the Oonopidae, and is classified with other similar, soft-bodied goblin spiders in the subfamily Sulsulinae.