Place the Chex cereal in a large mixing bowl and set it aside.
In a microwave-safe bowl, combine the chocolate chips, peanut butter, and unsalted butter. Heat in the microwave in 30-second intervals, stirring after each, until the mixture is smooth and well combined. Stir in the vanilla extract and salt.
Pour the chocolate mixture over the Chex cereal. Gently fold and stir until the cereal is evenly coated with the chocolate-peanut butter mixture.
Place the powdered sugar in a large Ziploc bag. Add the chocolate-coated Chex cereal to the bag. Seal the bag and shake it vigorously until the cereal is fully coated with powdered sugar.
Spread the coated cereal out onto a baking sheet lined with parchment paper to cool and set.
Once the muddy buddies have cooled, transfer them to a serving bowl. Add your Halloween-themed toppings - Reese's Pieces, Halloween sprinkles, and edible candy eyes. Mix them in for a spooky, colorful, and delicious snack.
