How was the Pixar Universe created

The most mysterious and saddest story in the history of animation belongs to Boo, which we know from the movie Monsters Inc. Sulley, one of the monsters that scares children, opens a door one day and Boo loves Sulley rather than being afraid. From that day on, an intense bond develops between them. But at the end of the movie, unfortunately, the two of them have to say goodbye to each other. While Sulley stays in the future, Boo returns to his own time. But little Boo can't get past this and misses Sulley terribly. She can't forget her kitty for the rest of her life. Years pass and she meets magic when she becomes an old woman. Thanks to this spell, he goes back to the past and starts to go through the doors, trying to find Sulley. Which brings us to the biggest mystery in the Pixar universe. Tiny Boo is actually the old witch from the Brave animation. So the essence of what makes up the entire pixar universe is actually Boo's endless love for Sully.