Bake cupcakes and let them cool completely.
Make frosting and divide it into separate bowls and color it red, green, black.
Fill three separate piping bags with green, red and black colored frostings.
Attach tip # 104 to the green and red piping bags.
Attach tip # 3 to the black piping bag.
Hold the red pining bag at a 45 degree angle along the edge of your cupcake. Squeeze the bag and pull towards yourself and you will end up with a red "petal."Continue to do this all around the cupcake until you have a full row of red petals. Then, work your way inwards and make another row of red petals. Finally, pipe a few petals in the center of the cupcake.
To make the seeds, hold the black piping bag at a 45 degree angle.Squeeze the bag and then pull towards yourself.Do this a few times randomly on each red cupcake.
Repeat step 6 on a few cupcakes but this time, use green icing. Don't pipe the black seeds on these green cupcakes.
Arrange the cupcakes in the shape of a watermelon. Enjoy!