Crambe crambe, commonly known as the oyster sponge or orange-red encrusting sponge, is a species of demosponges belonging to the family Crambeidae.

[1][2] The colonies of Crambe crambe form thin orange to orange-red plates, rarely lobed, with a very rough surface perforated by raised oscula found along the exhaling channels.

These demosponges often cover the shell of live shellfish (Arca noae, Spondylus and various sedentary bivalves).

Eupolymnia nebulosa sometimes hides itself on these sponges.

[3] This species is endemic to the Mediterranean, but it is also present in the North Atlantic Ocean, in the English Channel and in the North Sea.