I posted in your "other inverts" thread yesterday.
"Hi --
This is most likely a Tritoniopsis spp. They eat soft coral. Its a shame, because they are really awesome looking animals. I found something similar on a gongorian that came from the Florida Keys. I only ended up w/ two in total, but you may want to be on the look out for some more."
I would guess it is T. elegans (syn. T. alba), unless the coral in question was housed w/ gorgs from the Western Atlantic (or other things recently harvested from there.)