Halloween Poke Cake

Grease a 9x13 inch baking pan. Prepare cake mix according to package directions. Cool 60 minutes on a wire rack. Combine boiling water and gelatin in a small bowl. Stir until gelatin granules dissolve. Stir in cold water. Poke holes all over cake using a meat fork or wooden skewer. Pour gelatin over cake. Refrigerate 2 to 3 hours. In a medium bowl, beat butter until fluffy. Add powdered sugar, cocoa, milk and vanilla. Beat until smooth. Spread evenly over top of cake. Top with candied pumpkins. Store covered and refrigerated.