I can verify that yes, cats are their own type of liquid.
My Prince Fredward can fit in the tiny crawl space between my bed and the wall. I swear it can't be anymore than 2 inches, and he's almost 20 lbs!
He weathers the rooms' landmarks better than any glacier, and he's loud and forceful in a storm.
He fits inside any box he wants to, too!
I wish I had pictures of some of the things he's done.
Oh, and he's self cleaning! I'm even willing to call it a precipitation cycle!