Make cake mix batter according to package directions.

Scoop 1/2 cup of cake batter into bowl.

Scoop another 1/2 cup cake batter into another bowl.

In the first bowl add green food coloring until desired color is reached.

In the second bowl add red and blue food coloring until desired purple color is reached.

Line a muffin pan with cupcake liners and spray nonstick cooking spray in them.

Next add even amounts of each cake batter into each cupcake liner until about 2/3 full.

Bake according to package directions.

Once baked let cool completely.

Frost and decorate as desired.