Noo-Noo seems to be both the Teletubbies guardian and/or housekeeper, due to its resemblance to a vacuum cleaner, which is its initial purpose in the house. Noo-Noo hardly ventures outside, instead remaining indoors and constantly cleaning with its sucker-like nose. It does not speak like the other characters, instead communicating through a series of slurping and sucking noises. At times, Noo-Noo gets annoyed with the Teletubbies antics and can vacuum their food or toys. This usually prompts the Teletubbies to scold Noo-Noo through a cry of "Naughty Noo-Noo!". Usually after this, Noo-Noo flees and the Teletubbies pursue it comically around the house until they grow tired, are distracted by something, or forgive Noo-Noo. This sequence ends with them hugging it, or with it shooting out their absorbed objects.
(From Wikipedia, the free encyclopedia. GFDL)