Preheat oven to 350 degrees. Line a cupcake pan with yellow cupcake liners.
In a large mixing bowl, add in the yellow cake mix, water, vegetable oil, and eggs. Beat with a hand mixer on medium until incorporated.
Fill the cupcake liners ¾ full with the cake batter.
Place into the oven and bake for 15 to 20 minutes until done. Insert a toothpick and if it comes out clean or with moist crumbs, the cupcakes are done.
Let the cupcakes cool completely. Work on making the ghost toppers and frosting while waiting.
Ghost Toppers
Line a baking sheet with wax paper and roll your white fondant into 24 1-inch balls. Continue to roll the fondant until it's completely smooth.
To start forming your “ghost” shape, flatten the ball out to become an oval and then pinch the end slightly. Then bend the pinched end up to form a curve.
With scissors or a sharp knife, snip a little portion of the fondant on each side to form arms. Using a black food coloring marker or black frosting, draw two oval eyes.
Frosting
In a mixing bowl, add in butter, sugar, milk and 2 drops of red gel food coloring and 2 drops of yellow. Using a hand mixer, beat on low and gradually increase to high.
Add the frosting into a piping bag fitted with a straight tip or coupler. Add a swirl of frosting to the top of each cupcake.