Cleo Broflovski is the deceased mother of Sheila Broflovski that unusually shares her daughter's married name. Because of this, it can be assumed that it was Gerald Broflovski that took Sheila's surname.
She has only appeared on screen as a corpse in the third season Halloween special, "Korn's Groovy Pirate Ghost Mystery" when the boys dug her up in order to frighten the 5th Graders (who are now the 6th Graders). During the course of the episode, a dog ate the corpse, but later regurgitated it to the disgust of everyone at the Halloween festival. This is a parody of a scene in the cult horror-comedy film Braindead, in which a dying old woman regurgitates the body of a dog. Later, the boys managed to frighten the 5th Graders with her.
In "Quintuplets 2000", Randy Marsh, in an attempt to explain Mrs. Vladchik's untimely death to the girls, had all the kids who had a grandmother step forward; only a saddened Kyle did not forward, indirectly referring to the deceased Cleo.
In the sixth season episode "The Biggest Douche in the Universe" the psychic John Edward "receives a message" from Cleo for Kyle Broflovski stating that he is to look out for four white doves, which he sees at the New York Airport (having traveled there to feature on the show). Kyle sees the four white doves on an advert for a Jewish school named Jewleeard which he joins. After some convincing from Stan Marsh he finally realizes the psychic was just cold reading and returns to town stating that Cleo is "dead and gone forever".
In the episode "A Ladder to Heaven" when Stan and Kyle reach the clouds they look for heaven and Kyle exclaims, "Grandma?"
In the episode "It's a Jersey Thing" it is revealed that Sheila had grew up in Newark, and that her parents had lived there whilst pregnant with Harold. It maybe assumed that Cleo might had moved to South Park; like her daughter, to escape from New Jersey.
- "Korn's Groovy Pirate Ghost Mystery" - The boys use her to scare the fifth graders.
- "The Wacky Molestation Adventure" (mentioned only) - While Gerald and Sheila are being arrested for sexual child abuse, Sheila inquires as to where her children going are being taken. The social worker informs them that they are being sent to live with their grandmother, to which Sheila states, with surprise, that she has been dead for three years.
- "The Biggest Douche in the Universe" (mentioned only) - Kyle states that his grandmother wants him to attend a Jewish private school.
- "A Ladder to Heaven" (mentioned only) - Kyle calls out to her once he thinks that he, Stan and Cartman have gotten to heaven.
- "It's a Jersey Thing" (mentioned only) - Sheila mentions that she stayed with her parents in New Jersey.
Aside from Cleo Broflovski's appearance predominantly being that of a corpse, she appears to have gray hair and was buried wearing a gray gown with white, lacy trimmings.