Peel your apple and carefully push it into a pencil or paintbrush.
Sculpt features into the apple such as eyes, nose, mouth etc. The more bizarre your design looks, the better it will look when finished.
Add extra bits of detail if you wish. I used black peppercorns inside the eyes and grains of rice for teeth.
Leave your finished apple somewhere warm (I left mine on the kitchen windowsill)
After about a week, the apple will be shrivelled up on the outside, but still soft and squidgy on the inside.
And after two weeks it should be completely finished.