This is a good example of how Photoshop uses layers to create composite photos. There are three layers in this image, each taken from a separate photo:
1. The old Buick parked in a gas station
2. The lightning in the sky (See the next photo).
3. Eyes from a photo of a toad (in the headlights).
Here is a summary of how this image was made. First I selected and deleted the sky using the quick mask tools. I overlaid the deleted sky area with the lightning image on a new layer and shifted the color to red. Next I selected the eye from a photo of a toad and pasted it over one headlight as a third layer. This required that I resize and transform the eye to exactly fit the headlight. I made a duplicate layer of the eye and moved the duplicate to the other headlight (after flipping it horizontally). I then linked the two "eye" layers and merged them into one layer for both eyes. I shifted the color of the eyes to green using the "Hue/Saturation" tool.. To complete the affect, I airbrushed in beams of light coming from the eyes using a white color at about 3% opacity. Using the cloning tool, I cut out portions of the grill until it resembled teeth. This was accomplished by cloning the black shadowed area over the parts of the grill I wanted to "delete". I selected the chrome grill (teeth) and shifted the color to yellow. I also changed the letters on the license plate to spell "Bite U". The original photo of the car was taken in the Southwest in the middle of the day, but I wanted it to look like it was night time. The "Glowing Edges" filter and Levels adjustment provided just the right effect. Since the sky and the eyes were on their own layer, they were not affected. I had previously selected the grill, so I was also able to exclude the grill so it was not changed by the Glowing Edges filter and Levels. This was done by re-selecting the grill from the saved selection (Channel) and then "inverting" the selection so that everything but the grill was now selected (everything on the base layer, that is). I then applied the filter and levels adjustment to the selection only.