The Butter Sock is Sam's weapon of choice. As the name implies, it is a sock filled with a piece of butter. It is used by swinging it to gain momentum and then hitting someone with it.
It appeared for a third time in iStill Psycho, where she used it to behead one of the mannequins to make it look like Gibby was sleeping so he could escape. It is also revealed in this episode that Sam never changes the butter in the butter sock.
It was mentioned in iGo One Direction, when Sam offered to use the butter sock on Harry for faking continued illness.
It saw its biggest use in iRescue Carly, where Sam beats up a large group of delinquents (about 30 people) with it by turning off the lights and swinging away while wearing night vision goggles. Sam says she uses hard butter in this episode.
It was last referenced in iGoodbye, as when Carly and Sam are signing off, Sam says to the audience "keep your sock full of butter".
It would later appear and be mentioned in Sam & Cat.
- According to Dan Schneider, he originally intended it to be a sock full of quarters, but since Nickelodeon considered it too dangerous if someone would try it in real life, he changed it to butter. 
- In one of Sam's blog posts on icarly.com, she mentions the butter sock when she is listing things you can buy for 3 dollars. This is what she says: "One tube sock + One stick of butter = Instant butter sock. Cheap and effective!"