Preheat the oven to 350 degrees and line a small square pan with parchment paper.
Melt the butter in a microwave-safe bowl, then stir in the sugar until smooth.
Add the eggs one at a time and mix well after each addition.
Stir in the black cocoa powder, flour, and salt until no dry streaks remain.
Fold in the dark chocolate chips, then spread the batter evenly in the prepared pan.
Bake for 20 to 22 minutes until the center looks set but still soft.
Let the brownies cool completely in the pan before cutting into four squares.
Place two candy eyes on each square and add two short licorice strips below them to form whiskers.