Broome, Gantheaume Point, seaweeds

First I thought it was some kind of fish or sea creatures eggs, but then it looks more like a plant... or is it slightly different?

Is it one creature or is it a stone covered in a lot of little creatures? Alive like animals or like plants?

And some weird other things, especially this blue stuff. A chemical colour of light blue was attached to several spots on the rocks at low tide.