Pop the popcorn in batches using an air popper, stovetop pot or microwave bags, until the popping slows to one pop every 2 to 3 seconds.

Transfer the popped corn to one very large bowl or two medium bowls, discarding any unpopped kernels.

Drizzle a portion of the popcorn with melted butter and toss, then divide it into the smaller bowls for seasoning.

Sprinkle one bowl with parmesan, one with ranch seasoning, one with cinnamon sugar and one with chili lime seasoning, tossing each until evenly coated.

Set the caramel sauce and M&Ms in small bowls alongside for guests who want a sweeter mix.

Arrange all the bowls and seasonings together with a stack of paper bags.

Let guests scoop a base of plain popcorn into their own bag and top it with whichever seasoning or mix-in they like.