After the Fat Lady tells him that Sirius Black was her attacker, Dumbledore orders Filch to seal the castle. There's a scene of the large front portcullis coming down. As it does, we see a full moon in the sky and hear a certain werewolf howling. So, it seems he forgot to take his potion that night as well.
23. Dirty Laundry
When Animagi such as McGonagall (cat), Sirius (dog) or Wormtail (rat) change into human form, they are clothed. When Wormtail changes back into a rat, his clothing falls off. Yet he appears to be wearing the same outfit in Goblet of Fire. That makes you wonder how many copies of that suit are lying on the ground, somewhere. And where do their wands go when they change into their animal half?
22. Who Brings A Llama To The Quiddich World Cup?
Dobby and Winky were not included in the film version of The Goblet Of Fire, despite their integral position in the plot of the novel. However, while the Weasleys, Harry and Hermione are traveling through the Quidditch World Cup crowd to their tent, Ginny exclaims to Hermione, Look! Two house elves on llamas quickly (and blurredly) pass in front of the screen, and they appear to be wearing Bulgarian colours.
21. Neville Grows A Backbone
Since the Dobby character was eliminated, the task of giving Harry gillyweed for the second task went to Neville. Later, Snape accuses Harry of stealing it, along with boomslang skin and lacewing flies (the ingredients for Polyjuice Potion) from his private stores. We find out later that it was the fake Moody stealing the Polyjuice ingredients, but while its possible that Moody lifted the gillyweed for Neville, it would seem more likely that Neville overcame his fear of Snape to steal the gillyweed himself.
