slugs don't have shells.
He's a whole new breed of slug.
A fantasy creation of the conservative mind
But it exists and you did not deny it; loser!
It exists only in the fantasy world of the conservative mind.
So prove it does not exist., mrs fantasy!
That's impossible. I can't, nor can anyone, explore everywhere at the same time to be sure it doesn't exist somewhere I'm not looking at the moment.
Ridiculous request. You can't prove negatives. You should know that. Only someone living in a rich fantasy world could believe it did.