Critter ID?

[kreach]

I first noticed this little guy a couple months ago, but this is the first time he was in a place where I could get a picture of him.
He's about a half to three quarters of an inch long, has a mouth like a snail and appears to have a thin sort of flat shell that he ducks his "head" under when startled.
Any ideas on what he is?

 

[kreach]

I went back to look at him again and the longer I look at him, the more it seems like the "shell" is actually just flesh... but it does have a slight "shelf" that he pulls his head under...
Sorry... I know it's not a great description or pic...

 

[bang guy]

Stomatella varians.
Nocturnal diatom muncher. Great hitchhiker and very prolific if you have a male & female in the tank.

 

[thomas712]

I almost never seem to beat Bang Guy to these ID posts. You got a little flasher/siren that goes off when someone posts these Id messages or what?
Thomas
P.S. Don't let Tim S. E see that critter or he will look all over the world for some.

 

[tiffster]

I wish I was as smart as Bang guy...how did you learn so much about hitch hickers?

 

[macyjo]

i agree with bang--bang are these a favorite snack for crabs--ie arrow crab???

 

[carter]

I believe this is an abalone. they are a-sexual and reproduce singlely. they are great for cleaning algae. they grow quick and you may not see them all that often.....but they are cool to have.
Sometimes they just come out of the live rock when you buy it.