Can anyone identify this critter?

I saw this guy crawling around in my tank the other day. At first, I thought it was a stomatella snail, but it doesn't appear to have a shell. Does anyone know what it is?
critter 1.jpg
Critter 2.jpg
Just adding this for context. The critter climbs out onto the coral skeleton at the bottom left of the picture. I'm mainly putting this picture up because the close ups make my tank look filthy!
reef tank end view.jpg