Preheat your oven to 350 degrees Fahrenheit and line a 9x13 baking dish with parchment.

In a large mixing bowl, prepare the brownies according to directions.

Pour the batter evenly into the 9x13 pan, and bake according to the time on the box.

Allow the brownies to cool and set up firm in the refrigerator.

Cut the brownies into 8 rectangles, you'll have a little extra brownie on the ends to enjoy.

For the frosting, in a large mixing bowl, beat the butter, powdered sugar, and cocoa powder.

Add the salt, vanilla, a generous amount of black gel coloring, and milk, if needed, and mix until smooth.

Add the frosting to a piping bag with a writing frosting tip.

Decorate the brownies to resemble a spell book. For the eye candies, add a dallop of frosting to the back of them, and press into the brownie carefully.