Hitchhiker ID Please!!!

[cedarreef]

I recently found this really weird black thing that looks like a moving mushroom roaming around the tank when the lights are off. It has these little antenna-like things in front of it, too. It reminds me a lot of a nudibranch, but I'm not exactly sure. Any input on what it might be and if it's harmful would be great. Thanks!

 

[spanko]

Stomatella varia. A wonderful little snail critter that will help to keep the tank clean.

 

[cedarreef]

i do have those, but I don't think that's what this is. This doesn't seem to have a mouth or shell of any kind. It's also a lot bigger than the stomatella snails I have.

 

[spanko]

Well IDK then, probably gonna need a better picture.