What is this? Nudi?

[Reefmob]

Is this a nudibranch?
No exoskeleton looks like a snail with no shell

Black to dark blue and light blue dot about 1/4 to 1/2 inch
Looks like its grazing on the rock

Dead center

 

[cosmo]

I'm not sure as its hard to see, but I have a massive stomatella snail that looks a lot like that. Normally they're brown, but the come in all colors., mine moves a lot like that.