Snooter

Snooter is an imaginary friend that D.W. used to have, a winged pig. Some time ago, he got lost in the living room couch and was there until Nadine found him. D.W. decided that she didn't need him anymore and let Nadine keep him.

Arthur

 * "Postcards from Buster"
 * "The Making of Arthur"
 * "Bats in the Belfry"
 * "Through the Looking Glasses"

Cultural references

 * The premise of a flying pig is based upon the phrase "when pigs fly".