Melt the butter in a large pot over medium-low heat.
Once the butter has melted, add the marshmallows.
Keep stirring as the marshmallows melt. it will take a few minutes.
Once the marshmallows are completely melted, remove the pot from the heat and add the rice krispie cereal.
Stir quickly and get the cereal completely coated with the melted marshmallows.
Once coated add 1 cup of the fall candy. Stir to evenly disperse.
Spray a 9x13 pan with nonstick spray and dump the rice krispie treats mixture into the pan. I like to lightly spray my hands with the nonstick spray before pressing the treats into the pan evenly.
Then add the remaining fall candy to the top of the rice krispie treats.
Let it cool at least 30 minutes before cutting.