Euphylia eating flatworm?

[zedxplorer]

Notice this thing on the side of my frogspawn, it will shrink if I disturb it. Some sort of flatworm?

 

[tbrown]

Looks similar to a Polyclad for sure. I'd say it's highly likely since it's on a Euphyllia. Color and shape look right.

 

[zedxplorer]

Updates - I took out the coral for a dip and try to remove it with an exacto knife. To my surprise that thing has a hard shell on top of it and it is attached to the coral skeleton. Using the knife to get rid of the shell reveal a black soft body. I don't think flatworms have shell do they? Or is it some sort of snail?

 

[tbrown]

Flatworms do not have a shell.