Random play hitchhiker?

[mustseefish]

I noticed these random oaky like corals that came as hitch hikers on my live rock. Can anyone help identify them and let me know if I should keep them in the tank or get rid of them if they are bad for the tank? They started off as a brown color they’re now green

 

[EeyoreIsMySpiritAnimal]

They are palys... Not particularly good or bad but can spread, so if you're not fond of them, you might want to remove.