Cliona patera, commonly called Neptune's cup, is a species of demosponge in the family Clionaidae. Among the larger known sponges at up to a meter in height and width, the common name Neptune's cup refers to its characteristic wine glass shape and the Roman god of the sea. The species was thought to be extinct since the early 1900s due to overharvesting, but live specimens were discovered in 2011 off the coast of Singapore.