Egging someone else's property, usually a car, then covering it with slices of bread, and leaving it in the sun. The sun cooks the eggs, baking the bread and ruining the car. Hence, french toast.
A nasty person who resembles french toast... usually has the following attributes: greasy hair-syrup, bad smelling-burnt eggs, baby powder in hair to try to cover up the grease-powdered sugar. May also be a mysterious whore-nobody knows where it came from and is everywhere.