This is an image of the demon goddess Lolth, based on the callipygian drawing from the AD&D
Fiend Folio. It's intended to be not so much a representation of Lolth than an icon, a statue than could be found on the altar in Drow households throughout the Underdark, a holy object to which every good Drow youngster might be encouraged to whisper his or her every infraction against the Drow lifestyle (such as spiders inadvertently trampled) as well as secrets about his or her parents so that they might be punished accordingly.
Lolth in all her big-assed glory: