Grey Chalice sponge size 5".

Structure of this sponge is unmatched by many other sponges. 

Sponge is growing on a large live rock base, see pics.

Peppermint Shrimp, crabs and small fish like Goby fish love to host on this sponge shape.

One of a kind specimen of live sea sponge collection.

Center piece for any aquarium.

Note the Peppermint shrimp hosting on the sponge, the peppermints favorite home.