- For others named Rachel, see Rachel.
Rachel is the main antagonist and Lisa's imaginary best friend who tries to kill Lisa's real friends. She killed Janey Powell, Sherri, Terri, Dr. Mancluso-Gluckman, Milhouse, Snowball II, and Sergeant Sausage. She attempts to kill Marge and Homer but failed.
Lisa was playing hide and seek with Janey when a lawnmower suddenly turns on and runs her over, killing Janey. At her funeral, Lisa was talking with Sherri and Terri when a tombstone fell and crushed them. Traumatized by the deaths, Lisa goes to a psychiatrist, who is also brutally killed, making Lisa the main suspect for those deaths.
During a police search on her room, Chief Wiggum found sparkle nail polish, which was also found on the place of the deaths, and Lisa says that she only used it with Rachel. Later, Lisa was sitting with Milhouse on the school bus, but Rachel asphixiates him and Lisa gets arrested.
Later, Lisa managed to escape from prison with Bart's help and save Marge from Rachel, who was trying to kill everyone who Lisa loved, and as only Lisa could see Rachel, she would get blamed for the murders. Rachel then attacks Homer when he reveals his intoxication allows him to see her, and seemingly kills his imaginary friend, Sargent Sausage. Lisa then imagines Rachel as her mom married to a dentist, she fades out, disappears and wiped from existence forever. It also turns out she failed to kill Sargent Sausage, since imaginary friends can't die.
Rachel wears pink spaghetti straps, green ankle high socks with red stripes, and purple shoes. She has long brown hair and wears blue glasses. She also has pale skin.
- She could be Rachel Cohen from Today, I Am a Clown.
- She is briefly mentioned by Lisa in the Season 27 episode Much Apu About Something.