Line two 12 count cupcake tins with cupcake liners.
Combine the cake mix ingredients according to package directions for cupcakes and bake according to package directions.
Let the cupcakes cool.
Scoop the white frosting into a dish and add 3 drops of yellow food coloring and 1 drop of green (3:1 ratio). Stir to combine and repeat if needed.
Generously frost each cupcake with the bright green frosting.
Give each Zombie two eyes.
Use the black gel icing to make a mouth (or black frosting)
Use the Wilton red Sparkle gel icing to finish the Zombie with some 'blood'.
Repeat with all cupcakes.