ID please

[Mikeybones76]

Sorry for the crappy pic it’s in a really bad spot for pics but it’s definitely not one of the zoas

 

[Supa]

Aiptasia?

 

[Mikeybones76]

Aiptasia?

I hope not

 

[Joe31415]

Looks like it to me too. What happens if you shine a bright flashlight on it or poke it with something (or blow some water on it). While I know aiptasia can spread if you annoy it, I've found, in my very limited experience, that it'll quickly retract if you do so as well.
You could play it safe and get some aiptasia-x or superglue and just deal with it as if it's aiptasia.

 

[JGT]

Looks like majano.

 

[vetteguy53081]

Agree Majano
Using syringe, inject either lemon juice or better yet. . kalkwasser powder mixed with tank water into a paste the consistency of toothpaste and inject into the very center core and it will melt away