Boo
A two-year-old human child that has escaped into Monstropolis.
Where is she from?
Boo is sort of the mcguffin on Pixar's 2001 animated comedy Monster's Inc. She's a 2-year-old girl who's just having a grand time in a monster's world alongside 'kitty' her new big fluffy best friend. She was voiced by Mary Gibbs (which is apparently also Boo's real name), the 4-year-old child of Pixar story artist Rob Gibbs. Apparently, rather than try to confine a 4-year-old to a sound booth, they instead just followed her around for a few days, recording every sound she made.
Mary Gibbs is obviously now an adult. She did an AMA in 2015 when she was a freshman in college... while she doesn't do any voice work anymore, I have to say that if there's any property I'd love to see Pixar come back to, it's this one. It's so right up GND's wheelhouse to see how Boo & Sully's relationship evolves as she grows up.