Pizza in the Driveway

Yesterday morning I looked out the kitchen window and saw a slice of pepperoni pizza in the driveway. I thought to myself, "what on earth is a slice of pizza doing in the driveway???"

Then the mystery deepened... actually, it didn't. Later in the day I asked my mom about it. She said that she had put the pizza in the yard for animals to eat because it was too old. Something (more likely animal than alien) had moved it onto the driveway.