It's hard to tell exactly WHAT Noo Noo is, though he seems to be something like a vacuum cleaner! His job is to suck up tubby toast and tubby custard if the teletubbies spill it. Though I call it a "he", Noo Noo's gender is actually unknown. All Noo-noo ever says is "Vvvvt" and "noo-noo!".
