In a very large mixing bowl, combine Chex, Cheerios, pretzels, peanuts, and M&Ms.
In a smaller, microwave-safe bowl, melt 20 ounces of almond bark according to the package instructions.
Pour melted almond bark over the dry ingredients.
Mix together until well-coated.
Spread the chocolate mixture onto parchment paper to cool and harden.
Once the chocolate is hard, break the mixture apart and serve (or store it in an airtight container for later).