Small white things?

[KimberlyMary]

Started noticing these about a week ago. There was one single larger free floating one that I couldn't find when I came back to get it. They haven't moved. Any ideas?

 

[DDenny]

Looks like a possible sponge of some sort. Does it move or just stay in one spot?

 

[KimberlyMary]

Looks like a possible sponge of some sort. Does it move or just stay in one spot?

Stays in one spot! That's what I was thinking as well but found it difficult to identify via google