15 Facts About Monsters, Inc. on Its 15th Anniversary

Ahhhh, a childhood classic! Monsters Inc. celebrates its 15th anniversary and we love it so much, we just have to celebrate!

Here are 15 facts you may not have know about the hit film. 

1. Pixar came up with the ideas for Monsters, Inc., Finding Nemo, Wall-E and A Bug's Life over a lunch meeting in 1994.

2. Boo is voiced by one of the story artists' daughters.

3. Sulley has more than 2.3 million strands of hair.

4. Because technology wasn't advanced enough, Pixar had to develop a new program called Fizt to automate the movement's of Sulley's fur.

5. Boo's real name is Marry Gibbs.

6. In a Reddit AMA, the girl who played Boo revealed the story behind the song she sings while going to the bathroom. "They told me to sing and I started singing 'Wheels on the Bus,' but they couldn't use any actual songs [because of] copyright issues so they had me babble and sing random words for a few hours and took out the parts they liked the best!" she wrote.

7. Bob Peterson, who voiced Dug in Up, voiced Roz.

8. Randy Newman won his first Oscar for the film's closing song "If I Didn't Have You." He had previously been nominated 15 times in the Best Score and Best Song categories, but it was Monsters, Inc. that scored him the win.

9. Harryhausen's, the restaurant Mike takes Celia on a date to, is named after Ray Harryhausen, the legendary special effects artist known for creating monsters for films like Clash of the Titans and Jason and the Argonauts.

10. Sulley's terrified reaction of what he thinks is Boo going through a trash compactor is a direct reference to Chuck Jones' classic short Feed the Kitty.

11. Boo's toy collection is a treasure trove of Pixar Easter eggs. Among her toys are the Luxo ball, Jessie from Toy Story 2 and Nemo from Finding Nemo, which was released after Monsters, Inc.

12. The legendary Frank Oz voices Fungus, Randall's anxious assistant.

13. Bill Murray was Pixar's first choice for Sulley, but he never responded to their calls.

14. Mike Wazowski has cameos in Finding Nemo, Cars, WALL-E, and Toy Story 3.

15. John Goodman (Sulley) and Billy Crystal (Mike) recorded their lines together—a rarity in animation.