Preheat oven to 350. Line a 13x9 cake pan with foil, leaving a 2-inch overhang on 2 sides. Spray with non-stick spray.
Add pretzels to bowl of a food processor and pulse until they reach a crumbled coarse crumb texture.
Add pretzel crumbs, butter and sugar to a bowl and toss all together. Mix and stir to combine. Press into bottom of cake pan. Evenly sprinkle chocolate chips, peanuts, potato chips, toffee and peanut butter chips evenly over the crust. Top with milk. Bake until golden brown, about 25 minutes.
Let cool completely. Lift out of pan. Cut into squares.