Spray a 15'' x 10'' x 1 with non stick spray. Set aside.
In a large mixing bowl, combine the cereals, peanuts and M&Ms. Set aside.
In a medium sized saucepan bring the corn syrup and sugar to a boil, stirring frequently. Remove from heat. Stir in peanut butter and vanilla.
Pour syrup mixture over the cereal mixture in the large mixing bowl. Toss to coat evenly.
Spread mixture into prepared pan. Let sit until mixture is set.
