For the frosting, beat the butter until smooth, and mix in vanilla.
Gradually add powdered sugar, mixing well.
Gradually add 1-2 tbsp. milk to get your desired frosting consistency.
Lay out a long piece of plastic wrap.
Drop about ⅔ cup of the white frosting onto the wrap in a sort of straight line.
To the remaining frosting, add 3-4 drops of teal food coloring, and mix to combine.
Drop about 1 ½ cups of teal frosting onto the plastic wrap beside the white.
To the remaining frosting, add 3-4 drops of blue food coloring, and mix to combine.
Drop the remaining blue coloring beside the teal, and wrap up the plastic wrap up longways, twisting the ends.
Prepare a piping bag with a star tip, and snip the twisted end off of one end of the plastic wrapped frosting.
Place the wrapped frosting into the piping bag, with the end you snipped off facing down towards the piping tip.
To frost the cooled cupcakes, evenly squeeze the piping bag so that you get all of the colors piping onto the cakes at the same time for an ombre effect.
Pipe all the cupcakes and dd one shark gummy candy on top of each one.