Something like a stomatella or limpet?

[DragonForce]

Hey everyone, I have this creature that I've been trying to snap a shot of for the last few months that looks something like a stomatella or limpet but all the pictures I find do not point towards either. I would say its about 3/4 inch and it moves quick for what it looks like. If I were to guess I would say its a slug/snail hybrid but I don't think theres such a thing. Any guesses here? There are what appear to be raised white spikes all over it with 3 dark ovals running from its head down its back. I have 100% ruled out the chances of it being any nudi of any sort.

 

[MT79]

Looks like a chiton. They are usually peaceful grazers.
http://en.wikipedia.org/wiki/Chiton