I hope everyone who sees these photos says "Thats just a XXXX, you noob!" I don't know what these are. They are all over the inside of my skilter on my 30 gallon. There are NONE in the tank. The tank houses Zoas, leathers, a Tridacna, and Bill the Sepia Bandensis. The tops look like they are spines, but hopefully they are just filter feeders.