MICROWAVE chocolate and butter in large bowl on HIGH for 2 min.; stir until melted.
BLEND in sugar: Whisk in water and eggs, one at a time, until well combined. Stir in flour and baking soda; mix until smooth.
FILL 16 large cupcake cups with batter. Bake at 350°F for 25 min. Cool completely.
DECORATE cupcakes as desired, try Santa Claus, Mrs. Claus, reindeer, elves and angels using Cool Whip Topping, icing tubes, mini marshmallows, candy and pretzels.
serving size = 1 cupcake