Preheat the oven to 350 degrees and grease donut pans with nonstick cooking spray.

Beat together the cake mix, egg, butter, and milk in a large bowl.

When the batter is well mixed, transfer the mixture to a large piping bag. Pipe the mixture into the donut pans.

Bake in the preheated oven for 15 to 18 minutes, until a toothpick inserted into the center comes out clean.

Allow the donuts to cool in the pan for 5 minutes, then flip the pan over onto a wire cooling rack and allow the donuts to cool completely.

When the donuts are cool, remove the lid from the frosting jar and heat for 30 seconds to 1 minute in the microwave, until the frosting is slightly runny.

Drizzle the melted frosting over the top of each donut, then decorate with candy eyes and sprinkles.