snail id?

[tenMann2]

what type of snail can this be?
it is black/navy, looks to have a soft shell, the bottom is cream colored like other snails. I have only spotted it two times during the night.
is it safe? I don't know were it came from. I dipped the most recent frags I have been adding too. Attached some pics.

 

[KathyC]

I cannot see the picture very well but from your description it is a stomatella.
They have a small shell that sits atop their 'back'.
They are welcome in a reef tank.

 

[waynotcars]

Stomatella do not have black shells. Most of the stomatella snail is outside of the shell. The shell is clearish white pearlescent and is ovel shaped and flat, almost like a fingernail sitting atop the snails back.

 

[e.muehlbauer]

Its a limpet. If you watch it carefully, you may see an occasional flash of white on top. That's the shell, normally covered by the black mantle. They're harmless.