Find a white wall or backdrop.
Set up a strong, artificial, concentrated light source like a large flashlight or lamp. Let the light source shine on your hands and cast shadows behind you onto the wall or backdrop.
Form one hand into a fist. Allow your thumb to wrap across the outside of your knuckles so that it gives the appearance of a snake's mouth.
Place a small, very thin piece of paper between your first and second fingers. This is the snake's tongue.
Undulate your arm and hand to mimic a snake's movements. Let your snake writhe along the wall as if it were moving along the ground.
Use your free hand to form another animal to make the show more interesting. Choose an animal that is known prey for the snake so that you can set up a battle or chase sequence between them.