Coco was created by a little girl who was shipwrecked on a deserted island after a plane crash. Her only verbal utterances and written means of communication is "coco" (with each syllable pronounced "co"), which most of the imaginary friends, Mac, Frankie, Madame Foster and other characters can seemingly understand. This can lead to strange conversation. She usually is understandable to all, but may not be, depending on what jokes are needed. She also seems unable to write anything but "Coco," with similar rules applying to whether or not people can read it. Coco has been shown to be romantically involved with a lamp. When she is excited, scared, in love, or needs the attention of others, she has the ability to lay plastic eggs, similar to those found in Gashapon toy vending machines, that can contain anything from Ming vases to tickets for redemption of prizes to money or even auto parts. Often, these seem to fulfill whatever need the person opening them has at the time, though she won't take requests. Coco is about as tall as Frankie (who is around 5 and 1/2 feet tall). She can also swallow things, such as puppies, and make them reappear in eggs, she took three jobs — a fast-food employee, a mall courtesy desk clerk, and a security guard, all in the same day — to pay for a massage chair, and also reportedly has a vacation home away from Foster's. She can also alter her own coloring scheme, She makes up for her lack of arms with her feet, and has opposable toes, She also can drive the Foster's bus, and Coco is a talented artist. She may have a sense of violence (or a sinister, yet antagonistic side) as revealed in the episode "A Room With A Feud" when she (rather sinisterly) said "Co co coco." (pronounced in a way that possibly suggests she said "We could kill him") with Mac responding with "Coco, I think if we did that, we'd go to jail". She may also have a crazy side to her, as seen in "My So-Called Wife", where she was seen acting wild and uncontrollable, including bouncing along a diving board and playing a Sousaphone at the end and once licking a pole. We also learned that in the episode "Mondo Coco" that she talks to squirrels, became a tutor, an inspirational talker and author, a reggae singer, a Japanese TV celebrity who becomes Prime Minister, fell in love with a yeti, an airplane pilot and a supermodel.

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