Starfish bubble?

[AmberLee]

My Linckia starfish has some sort of bubble on it's arm, looks kinda see through. Like a blister?

I got him 10 days ago along with my LR so he's a hitchhiker, and the tank has just finished cycling.

http://i1380.photobucket.com/albums/ah191/Amba_Price/20150114_140919_zpscp9ghfaq.jpg (http://s1380.photobucket.com/user/Amba_Price/media/20150114_140919_zpscp9ghfaq.jpg.html)

http://i1380.photobucket.com/albums/ah191/Amba_Price/Mobile%20Uploads/2015-01/20150114_140600_zpssztjp6kr.jpg (http://s1380.photobucket.com/user/Amba_Price/media/Mobile%20Uploads/2015-01/20150114_140600_zpssztjp6kr.jpg.html)

[ardsman]

almost looks like some sort of egg cluster.

[AmberLee]

almost looks like some sort of egg cluster.

Silly question but, a starfish egg cluster? Or?