What is this?

[Kolby’s Reef]

It almost looks like a kenya tree but I’m scared it’s some pest or something bad for my tank. Only been in the hobby 8 months so still pretty new. This is starting to grow out from underneath some rocks as well

 

[BloopFish]

Look like a parazoanthus or a paly/zoa of some sort, they can bud off and grow in different places.

 

[reef lover]

The taller pieces are kenya...but the smaller polyp looks like as mentioned above or could be hydroids....