Egg Sac?

I thought this was a sponge at first, but then realized it could be an egg sac.

Stephen A. Cook Reef

1 Grouper Module and 1 Florida Limestone Artificial Reef. Deployed on 06/04/2008. Verified by divers Bob & Carol Cox on 4/19/2010module with rock panels. Deployed 06/19/2009. Verified by MBARA divers Bob & Carol Cox on 6 May 2012.

Reef Area: NorthSite
LAT: 29 46.932
LON: 85 42.711
Range: 17.89
Bearing: 235.4
Depth: 105 feet
Range and Bearing is taken from mouth of Mexico Beach Canal.