What are these hitchhikers?

I was kidding about fire, but I plan to use Kalk Paste to kill mine down the road.

 

Damn. Lolololololol. I really thought that was the answer. I will try the Kalk paste tho. Thnanx

 

Which is the clove polyp?

 

I was going to guess GSP that is recovering from lack of light, mostly based on the purple base.

Clove polyps, GSP, and xenia are all different types of encrusting or spreading soft coral that spread quite quickly and sometimes invasively.

Whatever it is it will probably survive a while in the dark. If you like the look of it I'd keep it, but keep the rock where the coral can't spread to other rocks. And also at the top so that you can take it out and sterilize the rock if it gets too obnoxious.

 

Soft coral do spawn and spread whther or not the are isolated on their own rock. Ask ExactlyBOP about xenia.

 

Thanks everyone for all your help!