Combine the chocolate chips, peanut butter, and butter, in a medium sized microwave proof bowl. Microwave for 1 minute, stir. Microwave for another 30 seconds if needed till you can stir smooth.
Stir in the vanilla extract.
Add the chex cereal into a large bowl.
Pour the chocolate mixture over the cereal and gently stir to coat the cereal completely with the mixture.
Add the cereal to a large gallon sized Ziplock bag, add in the powdered sugar.
Shake to cover the cereal completely with the powedered sugar.
Pour the muddy buddies into a clean bowl, and stir in the candy corn, pumpkins and reeses pieces.
Spread the muddy buddies out onto a baking sheet (or two) covered with parchment paper.
Allow to rest for about 20 minutes.