What is this wierd growth on my gonipora??

[EgotisticObeseChihuahua]

I have had this Goni for around 3 months and for the past few days it has been closed. Then today this growth started to appear. Any information on this would be helpful.

Thanks

 

[Rtaylor]

Can you circle what you’re referring to? I see something possibly resembling a barnacle, but it could just be a closed polyp, hard to tell from the picture.