Help with identification
 

I went to the LFS last week and purchased what i thought was just a normal leather coral. When I placed it in the tank it looked a bit different than in the store. I took these pictures back to the fish store, but unfortunately the man who sold it to me was off that day and the store assistant said it might be either a sponge or the foot of the coral. It is moving around like mad. Hopefully someone here can help me identify what it is.

Photos
 

Apologies for the sideways photos, I do not know how to fix this, as they are correct on my computer.

-M

Is it a finger leather of some sort, possibly. If it is soft.