Invertebrate identification

[Paul chenoweth]

Hi there,
I have this strange invert in my tank, started out about the size of my pinky finger nail, now it's the size of a golf ball.
Only comes out at night, it hides on the dark side of one of my rocks, wait about an hour after the light are out and out it comes.
It has holes on its back which some times has little tentacles come out of them and I have seen it discharge waste from them as well.
It's had me curious for 6 months or more, any info would be great

Thanks

 

[AbsoluteFaye]

Looks like an abalone.

 

[ccCapt]

Looks like some type of limpet, possible a keyhole limpet.
Limpet ID F2

 

[Swimzebras]

I say abalone too, I don't think limpets have the swirled shell.

 

[Paul chenoweth]

It's got a soft shell, seems to be flexible as it moves around the rock, moves pretty quick too.

 

[Paul chenoweth]

Hi all, thanks for your help.

I looked up photos of these two suggestions and I have to agree that it looks like an abalone.
Thanks for your help