Using a stand mixer, combine all ingredients and mix on medium speed.
Mix until you see stiffed peaks in your frosting.
Once the frosting is made, split it into 4 bowls.
Add about 2–4 drops of each color.
Add the Purple food coloring to the first bowl.
Add the Pink food coloring to the second bowl.
Leave the third bowl white.
Add a few drops fo the green food coloring into the last bowl.
Scoop the purple frosting, leaving about 1/4 cup in the bowl, into the piping bag with the round tip.
Scoop one spoonful of the Pink frosting onto one side of the piping bag fitted with all three size star tips.
Scoop one spoonful of the Purple frosting onto the other side of the piping bag fitted with the small star tip.
Scoop white frosting into the same piping bag as the pink and purple.
Scoop white frosting into the two other piping bags with just the pink frosting.
Scoop the green frosting into the piping bag with tip number 195.
Using the round purple piping bag, pipe a large dollop of frosting onto the cupcake.
Dip the cupcake into the sprinkles mixtures.
Pipe another dollop of purple frosting onto the top of the sprinkled frosting.
Using the large star tip, pipe a dollop of frosting in the top center.
Place the unicorn horn into the center of the frosting.
Place an ear on both sides of the horn.
Using the smaller star tips, pipe dollops of frosting around the frosting to create flowers.
Using the green frosting and pipe leaves along the flowers.