To make a scary shadow you have to have the light coming up. You can use this for even the tiniest mouse become the biggest giant.
Typically shadows have no color, and are just gray or black. But if you use a colored translucent material to cast a shadow, you then get colored shadows.
The shadow with the mind of its own
The point of this shadow is to get the knifes shadow to be a fork. to do this you have to the angle perfect and you get the shadow of the fork with the knife in the foreground.
The shadow that's alive
This shot is quite easy to achieve, and just requires a little imagination. The idea is that you photograph a shadow that looks to be using its surroundings.
Long shadows from above
This effect can create quite striking photos, but can be quite difficult to achieve with natural light. Using a low light source, such as the sun near sunset / sunrise creates long shadows.
Shadows on a translucent surface
You position your subject behind a semi-transparent surface, and then light them from behind. Their shadow is then visible through the translucent surface.
The techniques discussed so far involve using a flat surface to project the shadow on. Using a 3D surface to cast a shadow on can also give very interesting images. The shadow distorts and bends as it goes over the uneven surface, creating a very different feel to a standard shadow photo.