Preheat your oven to 250°F (120°C) and line a large rimmed baking sheet with parchment paper.

Place the popped popcorn and pretzels in a very large mixing bowl, ensuring all unpopped kernels are removed.

In a medium saucepan over medium heat, melt the butter, brown sugar, and corn syrup. Bring to a boil and let it bubble for 4 minutes without stirring, then remove from heat and stir in the baking soda.

Pour the caramel mixture over the popcorn and pretzels, tossing quickly with a silicone spatula until evenly coated.

Spread the mixture onto the prepared baking sheet and bake for 45 minutes, stirring every 15 minutes to ensure even crisping.

Remove from the oven and let cool completely. Once cool, break into chunks and toss in a large bowl with the candy corn, chocolate-covered peanuts, and sprinkles.