There have been loads of weird theories about Pixar movies. (Well loads of movies actually, people are bored.) I read one that suggested Toy Story 3 was about the holocaust, for a miserable example. There was another floating around that all their movies all exist in the same universe and are linked somehow. There are certainly plenty of easter eggs – most notably the Pizza Planet Truck:
But there are tons more and you probably missed them. I love Pixar and have watched their movies repeatedly and was nowhere near spotting most of these references. Well, Disney got in on this theory and basically confirmed it. All Pixar movies are linked – sometimes it is vague and tenuous but there are references to other films in all the films. If you get what I mean. If not, or you want proof, watch this video. Enjoy.