Preheat oven to 350 degrees. Line an 8x8 glass baking dish with foil then spray with non-stick baking spray.
Melt your butter in the microwave in a large microwave safe bowl.
Add the brown sugar to the butter to cool it down (so it doesn't scramble the egg) then add the egg and vanilla and whisk until the mixture is smooth.
Add the peanut butter and stir until completely incorporated.
Add the flour and stir until just combined.
Add almost all of the chocolate candies (set aside a few) and the entire cup of chocolate chips and fold into the mixture.
Pour mixture into prepared baking dish.
Top mixture with leftover chocolate candies, making sure to evenly spread out the blue and orange colors.
Mentally divide the bars into nine bars (like you would cut it) then add three monster eye candies to eat square, with one eye up top and then two eyes underneath like Fred's monster costume.
Bake for 25 minutes to until middle is set and cooked.
Allow bars to cool in pan for at least 30 minutes.
Remove foil from pan then cut into nine square bars with one set of monster eyes on each.