Gather all of your ingredients together, as well as your supplies. You will need two baking sheets lined with parchment paper, and three bowls to dye the dough different colors, plus a small bowl of sugar to roll the cookies in.

Preheat the oven to 325°F.

In a bowl, mix together the cake mix, powdered sugar, melted butter, eggs, and vanilla extract. Make sure everything is well combined.

Divide the dough into three bowls. Add food coloring to each bowl to create your desired monster colors!

Roll the dough into balls about the size of a tablespoon. Then roll each ball into the sugar.

Set each dough ball onto a baking sheet with parchment paper. Leave about 2 inches between each dough ball, as the cookies will flatten as they back.

Bake the cookies for about 8-10 minutes, until the tops have cracked and they look set.

While the cookies are still warm from the oven, stick the candy eyeballs on the cookies. Allow these to cool completely before eating.