Preheat oven to 350 degrees. Line a cookie sheet with parchment paper. Set aside.
In a bowl, add in the flour, cocoa powder, baking soda, and baking powder. Whisk to combine.
In a large mixing bowl, add in the butter and granulated sugar. Using a hand mixer on medium speed, beat until incorporated.
Add in the eggs and vanilla. Beat on medium until incorporated.
Add in the buttermilk and mix until combined.
Pour half of the dry ingredients into the wet ingredients. Beat just until the flour is incorporated.
Add the rest of the dry ingredients and beat on medium until all of the flour is worked into the batter. Scrape down the bowl and beat in any remaining flour.
Using a 2 tablespoon cookie scoop, scoop the batter onto the prepared cookie sheet about 2 inches apart.
Place into the oven and bake for 12 minutes or until done. Gently press the top of the pies, if they spring back they're done. If they stay sunk in, they need to bake a little longer.
Let cool completely.
In a large mixing bowl, add in the butter, cocoa powder, and 1 1/2 tablespoons of milk. Beat on medium until light and fluffy.
Add in the powdered sugar, vanilla extract, and the rest of the milk. Beat on medium until the powdered sugar is worked in.
Add in about 1 - 1 1/2 teaspoons of red gel paste food color and beat on high until incorporated. Add more red if it isn't red enough.
Add the frosting into a piping bag fitted with a star tip. I used a french star tip. Set aside.
Add the candy melts and refined coconut oil in a microwave-safe bowl. Microwave in 30-second increments and stir after each increment. Repeat until the candy melts are completely smooth.
Using a butter knife or spatula, spread a thin layer of candy melt on the tops of half of the whoopie pie cakes. Set the other half aside as the won't need sanding sugar added to them. Do one at a time so it doesn't dry before it's dipped in the sanding sugar.
Working quickly, dip the wet candy melt tops in the black sanding sugar. Make sure it's completely covered and set on wax paper to dry. Repeat with the rest of the 9 whoopie pie tops.
Grab the plain whoopie pie cakes that you set aside and pipe a swirl of frosting on each of them.
Add 6 SweeTARTS® Ropes to each swirl of frosting. There will be 3 ropes on either side of the whoopie pie.
Add an extra bit of frosting to cover the ropes.
Add the sanding sugar topped whoopie pies on top. Give it a twist to make sure it's firmly on the frosting.
Reheat the candy melts. Add a small amount to the back of the eyes and add them to the tops of the whoopie pies. Let the eyes dry completely.