Mushroom white Growth

[shrtwrec20]

Hi
I'm hoing you can help me. I'm fairly new to this hobby and my first coral, a mushroom, has been doing some funny things since i've had it. There are 5 mushrooms of the same variety on the rock which I purchased but only one is doing these strange things. It starts to close up now and again and instead of lying flat on the rock like the others it looks more like a tulip or rose, then after a while it goes back down. Sometimes it looks larger then smaller then larger again on quite a regular bases. I also noticed today it has a fairly large white growth on it's underside which is only visible when in tulip/rose form. Please what could this be, do i need to worry, take it out? I have tested all water parameters and they are all spot on.
Thanks in advance

[crvz]

Welcome to TRT! It could be a pest of some sort on that mushroom, I'd pull it out of the water and examine it a bit. They can stand being out of the water for a few minutes, and if you could snag a picture all the better.

[shrtwrec20]

it has detatched itself today and is now sitting on another rock nearby. When I get in from work I will see if I can fish it out and will take a photo. How do I attatch photos to this post?
Thanks