Preheat oven to 275 degrees F.
Line a large cookie sheet with parchment paper. Set aside.
In a large bowl, add all cereals, pretzels, and peanuts. Set aside.
Put butter in a small microwave safe bowl. Melt in microwave, about 1 minute.
Add brown sugar, vanilla, and pumpkin pie spice to the melted butter.
Stir very well and pour over the cereal mixture.
Gently toss the cereal/butter mixture until well mixed.
Pour cereal mixture onto prepared cookie sheet and spread out evenly.
Bake for 45 minutes. Remove the cookie sheet from the oven every 15 minutes and toss the mixture so it bakes evenly.
Add candy corn and toss so everything is mixed together.
Store in an airtight container for up to 1 week.