8. The Masturbating Monkey - Harry Potter & The Chamber Of Secrets
In addition to keeping overt, graphic violence out of kids' films, it's also smart not to make supposedly family-friendly entertainment too sexy.
Unfortunately Harry Potter and The Chamber Of Secrets had a bit of an unintended gaffe in this department when Professor McGonagall (Maggie Smith) is taking one of her classes at Hogwarts.
Keep your eyes peeled to the left-hand side of the screen and you'll notice a monkey hanging in a cage. Look closer and it appears to be, uh, playing with itself as McGonagall takes her class.
Though this is clearly just a mistake that made it through editing, the fact that director Chris Columbus cuts directly to awkward reaction shots of the main cast members, including Harry (Daniel Radcliffe), Hermione (Emma Watson), and Ron (Rupert Grint), almost makes it seem purposeful.
Now, there's nothing inherently wrong with animals acting on their most natural and innate urges, but it's probably best to keep it out of films made for kids, lest their parents be bamboozled with a few unexpected questions.