Need Id Asap

I had a hitchhiker snail that I haven't been able to figure out what it is... I just saw it again and it has tripled in size! I snagged him out of the tank and got some decent pics. I really don't want to put him back in until I can get a good id on him, any help is appreciated! Some pics are attached below.

He is one half or less shell, the other half or more is his foot. His is a dark color, almost looks like a freshwater snail you would see randomly in a pond or something. No "seashell" looking shell, just plain. Maybe 3/4"??

 

it looks like the slugs i have in my tank i have seen a few mostly at night if it has a half a shell could be the same never noticed it doing anything bad just seems to scavenge

 

Haven't noticed anything BAD yet, would like to make sure. Any other ideas??

 

Took 2 more pics before I tossed him back in. He hasn't shown any aggressive nature, I will definately keep an eye on him. Man and I wonder why people still want to throw live rock into their tank...

 

If it has a flat hard shell on the top like a fingernail I would say its an Abalone.

Harmless.;D

 

Or a stomatella snail

 

This is the extent of my knowledge on snail IDs. hahaha

http://www.3reef.com/forums/id/snail-ids-42666.html

 

Yup Stomatella for sure

 

Thanks everyone, I appreciate it! I will have to look up more info on stometella for sure, but I have to be at work in less than 7 hours! I'll post what I find! +3 for any help!

 

I agree with stomatela

if it were abalone would be much much much larger