Episode 145 of "Malcolm in the Middle"
s07e16 Lois Strikes Back
Title: Lois Strikes Back
Original Air Date: 03/19/2006 on Fox
Plot Outline:
When four popular high school girls play an evil prank on Reese by pretending he has a secret admirer and then dropping a pig off at his front door, Lois comes to his rescue. She plots her revenge on the four unsuspecting girls and wreaks havoc on their adolescent lives. Meanwhile, Hal realizes Lois is at a dangerous emotional place so he decides to get some distance and stumbles upon the idea for making his own pitching machine out of stuff in the garage.