Most of the humor written with children in mind is pretty on the nose. And while a lot of it is definitely funny, sometimes the adults in the room get a little bored. Parents almost never get the luxury of watching a movie once, especially if it’s their kid’s favorite.
So, working with their audience in mind, writers and animators will occasionally embed tiny pieces of mature content into their work. When done correctly the jokes catch the attention of the right people, but fly under the radar of any youngsters who might be watching too.