Mary Gibbs (voice of Boo in Monsters INC) was too young to sit to record her lines so they followed her around with a mic
“Mary voiced the part of Boo, the toddler girl in Monsters, Inc. (2001). As she was only two-and-a-half at the time of filming, she had trouble sitting still to record her lines so the studio followed her around with a microphone.
Monsters, Inc. is a 2001 American computer-animated comedy film directed by Pete Docter, produced by Pixar Animation Studios and released by Walt Disney Pictures. Co-directed by Lee Unkrich and David Silverman, the film tells the story of two monsters who work for a company named Monsters, Inc.: top scarer James P. Sullivan (voiced by John Goodman)—known as “”Sulley””—and his one-eyed assistant and best friend, Mike Wazowski (voiced by Billy Crystal). Monsters generate their city’s power by scaring children, but they are terribly afraid themselves of being contaminated by children, so when one enters Monstropolis, Sulley finds his world disrupted.
Docter began developing the film in 1996 and wrote the story with Jill Culton, Jeff Pidgeon, and Ralph Eggleston. Fellow Pixar director Andrew Stanton wrote the screenplay with screenwriter Daniel Gerson. The characters went through many incarnations over the film’s five-year production process. The technical team and animators found new ways to render fur and cloth realistically for the film. Randy Newman, who composed the music for Pixar’s three prior films, returned to compose its fourth.
Although the film suffered from two lawsuits against the filmmakers, filed by Lori Madrid before the film’s release and Stanley Mouse in 2002 respectively, that were ultimately dismissed, Monsters, Inc. was praised by critics and proved to be a major box office success from its release on November 2, 2001, generating over $562 million worldwide.
Monsters, Inc. saw a 3D re-release in theaters on December 19, 2012. Its prequel, Monsters University, directed by Dan Scanlon, is scheduled to be released on June 21, 2013.”