With one HUGE push, you move the dial to the cat position on the compass. Nothing much seems to happen, so you put the thing back in the sandpit and leave.
As you are walking along, you fell a slight irration in the hind quarters. After checking to make sure nobody's looking, you pull down you trousers a little bit, only to find a small tail growing in your underwear.
Suddenly, your nails sharpen and turn black. The rest of your hand becomes covered in fur as your transformation begins. The fur spreads like wildfire to you chest and back, while your ears grow pointed and shift to a comfortable position on top of your head. The world around you seems to be getting bigger; or are you getting smaller? In seconds, what used to be you is now a small, brown cat tangled up in some clothes.