Preheat the oven to 250F (121C)
Mix Crispix, Pretzels, and Pecans together in a large bowl.
Grease a large baking sheet, and pour the dry mixture onto the sheet. Flatten it out so it is evenly dispersed across the sheet. Set aside.
Heat up a pan on medium heat. Add butter, sugar, and corn syrup to the pan.
Keep stirring as the butter melts, making sure to scrape the sides and bottom of the pan as you stir to prevent burning.
Continue stirring for around 4 minutes until the mixture is fully melted and combined.
Once fully combined, pour the mixture over the dry ingredients on the baking sheet. Toss well to evenly coat.
Bake for 1 hour, stirring every 15 minutes.
Remove from oven and immediately add sprinkles while the Sweet Trash is still sticky. We added holiday sprinkles when we made this around Christmas time, but any sprinkle mixture will work!
Let cool and serve!