The first film in the cinematic versions of the Harry Potter book series, Chris Columbus's direction showed us audience members how magical the cafeteria can be in a school for wizards.
For Halloween, the Great Hall of Hogwarts (with the enchanted ceiling) has hundreds of floating jack o' lanterns twirling overhead. It's as if the Great Jack o' Lantern Blaze took place in zero gravity.
Are the students gazing up at the display? No, they're gorging on the best Halloween buffet ever constructed. Unlimited (it's magical, remember) portions of candy, cookies, apples, pastries, lollipops and more in tiered displays as far as the eye can see. Peppered among the sweet smorgasbord, are more carved pumpkins.
It's a shame that this is the most that the Harry Potter film franchise delved into Halloween-proper. Though I have a soft spot for Prisoner of Azkaban with its giant pumpkin patch and werewolf, this is the film with the Halloween scene with the most flavor (no pun intended).