Aliens (Sue Ellen Moves In)

One species of aliens has large, bulgy brains.

Buster imagined that Sue Ellen was one of them in "Sue Ellen Moves In."

Although a different species of alien stole the snowball in "D.W.'s Snow Mystery," Buster imagined that these aliens did it. At the end of "Return of the Snowball," it is revealed that they indeed did steal the snowball.

Buster imagined that they came to Earth to capture a human in "I Owe You One," and picked Arthur, but they allowed Buster to be taken instead because Buster owed Arthur favors and he really wanted to finish his book.

Appearances

 * Sue Ellen Moves In
 * D.W.'s Snow Mystery
 * Return of the Snowball
 * I Owe You One