Unknown coral like thing on my rock

[Pennycrayon]

Hi guys,

I recently purchased a mushroom and didnt realise it had something on the rock.. i tried to research it by myself but couldnt found any answers to what it was.

There is something that looks like some type of coral attached to the rock. I've

added a picture of it.

Can anyone tell me what it is ?

Thanks

 

[spidercrab]

some sort of macro algae not sure of the type.