Wat is this???

So while picking out some vermatid snails i've been noticing these things. Anyone have an idea what they are and if they are bad? looks like grassy stuff but idk

 

I can't see pic 2 (just keeps spinning), but if I'm looking at right thing in pic 1 (the white branch thing)...

I forget what it is called, but they pretty much only grow in the shade and are some kind of macro algae. Beneficial or benign at least.

They aren't something you have to worry about taking over or anything.

 

I am not sure what they are but have had them in my tank with no issues.

 

They're cool lookin'

 

Consider hydroids if they spread.

 

I dont think they are hydroids they look like micro brittle star arms just sticking out but they are because there planted on the rocks. Even when touched they appear to have no reaction i have just tiny spots of them around the tank but alright hopefully aint nothing bad