Fan Theory: Boo Grows Up to Become the Witch in Brave
What's There
In Monsters, Inc., Boo learns that magic doors can connect to other times and places, and becomes fixated on finding Sulley again after he's sent home. In Brave (2012), the Witch who transforms Queen Elinor into a bear has the ability to imbue objects and animals with sentience and travel through similar doors — and keeps a carved wooden figure of Sulley in her cottage, already documented in this catalog as a genuine Pixar Easter egg previewing Monsters University.
Why It Matters
Fan theorist Jon Negroni popularized the idea that Boo, obsessed with reuniting with Sulley and armed with knowledge of magic doors, eventually travels back to medieval Scotland and becomes the Witch — explaining her Sulley carving as a memento rather than a coincidence, and her sentience-granting magic as the in-universe origin of every other Pixar film where objects or animals come to life. It's the centerpiece claim of "The Pixar Theory," a fan-made unified timeline connecting the whole Pixar filmography. Pixar has never confirmed this, and there's no official statement supporting a Boo–Witch connection — it's a genuinely speculative reading of a coincidence (or a deliberate Easter egg reused for an unintended purpose), not a sourced fact. That's why this entry is labeled Fan Theory rather than Confirmed or Likely, unlike the real, director-confirmed Easter egg it borrows as evidence.