The Alien Huntress

Cast (in order of appearance): Jack, Dr. Brainstorm, Sheila Brainstorm, Calvin, Hobbes, Socrates, Andy, Sherman, Galaxoid, Nebular, Calvin's mother, Calvin's father, Rosalyn, Susie

Summary
An unlikely villain attacks Calvin after leaping to the conclusion he's an alien.

Full plot
Jack goes out to get the mail one day, and he sees a letter from Dr. Brainstorm's sister, Sheila, who is coming over that day, to Brainstorm's horror. It turns out Sheila is even more insane than her brother, and she's eating Brainstorm and Jack out of house and home. Brainstorm and Jack try to get rid of her, and Jack suggests sending her to Calvin and Hobbes, which they do. Sheila robs a Radio Shack for spy equipment and steals a car. She spots Calvin and the gang playing Calvinball. At that moment, Socrates gets a transmission from Galaxoid and Nebular, which causes Sheila to think that Calvin has a transmitter in him. Sheila tells Brainstorm about her discovery, which Brainstorm and Jack already know, but Sheila thinks Calvin has the transmitter and will get it out. The next day, Calvin comes home from school, and after Hobbes pounces, Sheila helps Calvin up and brings her inside. Mom and Dad announce Rosalyn is coming to babysit. Calvin and Hobbes prepare for Rosalyn, and Calvin goes to get Sheila and is knocked out by a sledgehammer. Calvin awakens in the attic and Sheila tells him she'll kill him if he makes a move. Mom and Dad are hypnotized into the basement, and Hobbes joins them, deducing she's Brainstorm's sister. Rosalyn shows up and is also hypnotized, as well as Andy, Socrates, Sherman, and Susie. She finally goes up to Calvin again. Socrates frees the gang and they go rescue Calvin. Eventually, Brainstorm shows up and brings Sheila to his mother's house. Socrates thinks the idea of a chip in someone's brain is the craziest thing he's ever heard, as the others laugh nervously.

Transcript
The Alien Huntress Transcript

Trivia

 * This is the Season 2 finale and the 69th episode overall of Calvin and Hobbes the Series.
 * The episode debuted in the Calvin and Hobbes Marathon.
 * This is Sheila Brainstorm's debut.