Purple cyano?

While that one does appear similar, the Purple Encrusting Sponge grows as a simple, thin layer over the rock, hence it's name.

That one appears to be a Purple Elephant-Ear Sponge.

 

I have something similiar, it is a slimy encrusting pink sponge.

 

Let me try again. I know few 3reef members have had the sponge in OP before ..it was in the ID section.

 

uh..no dosnt seem to be any mouths..by the way, the purple thing in the picture I posted, is little bit more darker. But its definatly purple something..

 

While the encrusting sponge has the word "purple" in it's name, it actually comes in a variety of colors from pink to purple, but may also be gray.

Absolutely. When using true live rock/sand in a marine aquarium, it's not that uncommon for some type of sponge to crawl out of the woodwork. Encrusting and pineapple are the two most common hitch-hikers, but there can be others.