Cousin of the Addams Family
Nobody ever found out where it came from. It was short, blonde, had no arms, sorta shuffled around, said stuff in gobbledygook, like Charlie Brown, they could understand it, we couldn't. He liked to live in the chimney when it wasn't in use.
In the movie, he had a higher pitch voice, drove, and got married to a human female. In the sequel they had a baby, a little tribble named "What." The name came from the Obstetrician.
yclept says Actually, Cousin Itt does have arms if you go back and look at the old comics. They're skinny and rather scary and hidden under all that hair....