Cats are commonly understood to be solid animals with bones, muscles and other structures that should, theoretically, prevent them from folding themselves into a container designed for something half their size. And yet, cats continue to demonstrate an apparent ability to ignore all of that.

Give a cat a box, and it will find a way to fit inside. Give it a bowl, and it may somehow arrange its entire body around the edges. Put a cat somewhere with absolutely no obvious room to sit, and there is a decent chance it will figure out how to occupy the space anyway.

The result is a collection of cats that look less like solid animals and more like a substance that was poured into whatever container happened to be available. Their bodies stretch, compress, fold, and spill over edges in ways that make the existence of a skeleton seem increasingly questionable.

Of course, cats do have bones. But looking at some of these pictures, it is easy to understand why the internet has spent years treating the concept of liquid cats as a serious scientific theory.

Maybe cats are not actually liquid. Maybe they are just exceptionally flexible animals with an impressive talent for finding comfortable positions. But until someone can explain exactly how a cat managed to fit into a space that looks approximately the size of a shoebox, the liquid theory remains worth considering.

Here are 20 cats that are doing their best to prove they are not solid.