Can anyone ID this

[K&AReeFers!]

Hello everyone I'm new to R2R and hope that I can get some advice and more info on reef tanks. Had my 75g tank for about a year and everythings going good but had this appear recently and don't know what it is. Doesn't really bother anything that I've noticed. Thanks

 

[Elementalj]

Corynactis?

 

[cloak]

Hidden Cup coral.

 

[K&AReeFers!]

Good or bad?

 

[Elementalj]

Good or bad?

I'll second the cup coral now. They're usually harmless.