What are these?

[Black42]

found this on the bottom of a zoa plug, and the zoa colony has lost polyps and tissue in the past month or so.

 

[zoasandpalys]

Not sure what kind of pod is on the left but the two spots on the right of it look like Asterina Starfish and those will start to eat on corals if they can not get food else where. I would kill all 3 and check for others. make sure you look close on the skirts and base of the polyps also not just the rock or plug they are on.

You can find a lot of knowledge with pictures just googling (reef tank hitchhickers), Good luck