Pop popcorn and combine with cereal, pretzels, and peanuts in a large mixing bowl. Combine sugar, syrup and peanut butter in a sauce pan and cook over medium heat, stirring constantly, until it comes to a full boil. Continue to cook and stir for 2 additional minutes and remove from heat. Pour sugar mixture over the popcorn and stir until all pieces are well coated. Spread warm popcorn into a single layer on a baking sheet and drizzle with melted chocolates and decorate with sprinkles. Allow chocolate to harden and break into pieces to serve.