ID please.coral?
 

Could anyone tell me what this is. It was a hitchhiker in my rock and popped out of nowhere. The picture is a few weeks old and it's about 3/4inch tall now and looks the exact same. Thanks in advance

Look like a leather coral to me.

Updated pictures. Behind the toadstool

Also what are these pink flower like things that are starting to take over one of my rocks

coral
 

star pollups

Looks like some kind of a leather and those things taking over your rocks look like clove polyps. I had them in my tank and they took over everything. Got to the point that I wanted to take my tank down. Good luck with them and hopefully they're not as evasive in your tank as they were in mine.

Leather coral and possibly clove polyps although they may be glove polyps. I have glove polyps and they don't grow for me. :) Leave them be for a bit and see what they grow up into.