In a small pot, bring water and sugar to a boil and whisk in cocoa, vanilla, salt, and corn syrup. Whisk until all of the solids have dissolved. Reduce sauce until slightly thickened. Strain and cool to room temperature. Pour into squeeze bottles. Squeeze into cold milk and stir for delicious chocolate milk or serve on your favorite ice cream. And, hey, it's fat free!
Recipe courtesy of Alton Brown