. . . if you're a Trick R Treater you fill your bag with freshly popped popcorn.
If you're giving out candy, well, don't do that. Instead, choose a type of condiment or sauce-BBQ sauce, ketchup, mustard, relish, whipped cream, maple syrup, aerosol cheese product, powdered parmesan, worcestershire sauce, mayo, nacho cheese product, biscuit gravy, butter-that comes in a squeeze bottle. When people with bags of popcorn come to your door, squeeze out whatever you got onto the popcorn inside the bags as they are presented to you.
If you're someone with a bag full of popcorn, you've got decisions to make. Do you go door to door trying to get as many people to squeeze off as many different kinds of sauces all over your popcorn as possible? Or do you eat each squeezed upon layer as you go so as to avoid mixing the condiments all together? Rest assured that different people will make different decisions as suits their tastes and preferences. So should you.
Overall, I think this represents a flavorful new way to celebrate Halloween!