Hitchhiker Zoa ID

[Benga]

Hoping someone with a good eye can figure this one out. I just noticed this little guy in the back. Definitely doesn't look like aptasia but it's not zoa of mine. Any idea what it is? I'm a little concerned because I found another much smaller one in a completely different area of the tank so want to make sure they're not invasive like aptasia.

 

[JGT]

Appears to be a ball anemone.

 

[Benga]

Appears to be a ball anemone.

Bingo that's what it looks lik after some google image search of thst. Hmm I'm reading that they can harm zoa colonies, you happem to have any experience with them by chance?