Unknown creature in my saltwater tank

[BryceJohn39]

I have had a couple of these things pop up and I’m not sure what they are seen to be small little tick looking creatures but don’t seem to be affecting my corals at all they are all growing still and water quality is good if anyone knows let me know thanks!

 

[Cell]

Pineapple sponge

 

[jayala12]

Does it move ? Kinda looks like a pineapple sponge