Unidentified object/sponge like substance on sand bed

[mcgallagherc]

Just knoticed this tonight, 2 sponge like substances are laying on the sand bed. I do have a mushroom rock with something growing on it that you guys help me identify as sponges. I removed them but see these 2 tonight. Thanks in advance

 

[anthonygf]

Need more pictures! haha, Take one out and get a better look at it.