Friend or foe. Slug and shell?

[linzlou4]

Moved my frag rock and got these interesting creatures!

Both have faces and antennae. On has a shell (lighter) the darker one doesn’t.

 

[EricR]

Light one looks like a stomatella snail = good.
Can't see the dark one well in the pictures but maybe search "fleshy limpet".

 

[WalkerLovesTheOcean]

Like said above, the lighter one looks like a stomatella - good CUC.

The darker one may be an elephant slug. They do have shells, but they take there flesh and cover it, so it looks like they dont have a shell. Will need better pics to make sure that's what it is.