• Line an 8 x 8-inch baking pan with parchment paper (or foil) and lightly spray with cooking spray. Set aside.
• In a large pot, add butter and place over medium heat. Melt, stirring occasionally. As soon as butter is melted, add miniature marshmallows. Stir constantly until marshmallows are just melted.
• Remove from heat and stir in salt and vanilla. Separate the mixture evenly into 2 bowls. Dye the marshmallow mixture in one bowl green and the other bowl orange.
• Add 3 cups rice Krispies cereal to each bowl. 

For the Frankenstein Krispies

• Mix all ingredients until well incorporated, then press mixture gently into the prepared pan. Lightly spritz your hands with cooking spray and gently press down the Krispies treats. Pressing too hard will lead to a denser Krispie treat.
• Set Krispies aside to harden a bit. Meanwhile, add the black candy melts and vegetable oil to a microwave-safe bowl. Microwave in bursts of 15 seconds, stirring between each burst for 10 seconds, until the chocolate is melted and smooth.
• Cut out the Krispies into 12 even bars. Dip the top of each bar in the melted chocolate. If desired, add chocolate sprinkles to the top. Using the remaining melted chocolate and a spoon, carefully spoon some of the melted chocolate onto the back of the edible eyes and press to attach right below the “hair.” Do the same for the miniature Reese’s on both sides of the Krispie treat.
• Let harden, then use the black food gel to pipe a zigzag line for a mouth.

For the Pumpkin Krispies

• Mix all ingredients until well incorporated, then lightly spritz your hands with cooking spray. Grab a handful of the Krispies mixture and gently form into a ball. Avoid compressing too much to avoid a hard/dense treat.
• Press a miniature Reese’s cup to the top of the pumpkin and reshape as necessary to form the ball and get the Reese’s cup to hold in place.
• Press in 1–3 miniature M&M’s to look like small leaves.