Pearl Pebbles Slaghoople is the mother of Wilma and mother-in-law of Fred, whom she hates very much and she looks just like Wilma but her build is that of a man (mainly Fred's) vice versa. She has three other children besides Wilma.
It's unknown if Slaghoople is Pearl's name from a second marriage (since Wilma's father was said to have died) or if Pebbles is her middle name, first marriage name or maiden name. More than likely it's placed where it is to avoid confusion with Pebbles Flintstone.
"Trouble-in-Law": In her first appearance, Pearl arrives to take over the housekeeping when Wilma sprains her ankle. It quickly emerges that she has sold her house and is planning to move in with Fred and Wilma, and pretty much moves Fred into the garage. Later, while playing golf, Fred is introduced to Melville J. Muchrocks, a Texas millionaire, who reveals he's looking to find an elderly wife. Keen to get rid of Pearl, Fred sets her and Melville up. Wilma is instantly suspicious of the would-be suitor. Her suspicions are seemingly confirmed when she and Betty overhear a juicy piece of gossip at the beauty parlor when a woman tells her friend about a notorious conman who marries rich widows for their money and then disappears, and who is rumored to be in Bedrock, posing as a Texas millionaire. Shocked, Wilma and Betty tell Fred Melville's a crook, and that he's going to propose to Pearl that night. Fred and Barney sabotage the date and post Melville back to Texas. The next day, however, it's revealed Melville wasn't the "Love 'Em and Leave 'Em Texan" Wilma and Betty had heard about. Wilma's mother almost leaves, because Melville had sent her a check for a good sum of money, but she postpones her trip when Fred hurts his back.
"Mother-in-Law's Visit": Fred and Wilma are expecting a baby, and Fred is trying to be more considerate, but his patience is tested when Pearl pays a visit. In order to pay for the crib Wilma wants for the baby, Fred secretly takes a second job as a cab driver. Disguised, Fred takes Pearl to several places where he normally hangs out, including the pool parlor and the bowling alley as well as the library. Pearl makes a bet with the driver that Fred isn't in the library, but Fred slips off to the reading room and removes his disguise. Pearl finds him there, meaning she's lost the bet, and feels she's been wrong about Fred all along. Fred almost gets away with it, but, just like in The Flintstone Flyer, Barney blows his cover by wearing the disguise in front of Pearl. Realizing she's been tricked, Pearl starts chasing Fred around the garden, beating him with a broom.
"Foxy Grandma": Pearl has gone home, but Fred hurts himself after walking on some broken dishes. When Wilma suggests calling her mother, Fred will have none of it. Instead, he chooses to hire a housekeeper, but each one seems worse than the one before, including one who eats everything she can get her hands on. Fred is convinced he has found the perfect housekeeper when he hires an elderly woman called Dinah. Unfortunately, she turns out to be the notorious bank robber, Grandma Dynamite. Luckily, Pearl arrives, having been called by Wilma, and she sends the robbers packing. However, Grandma Dynamite accidentally grabs Pearls luggage instead of her suitcase full of stolen money. Pearl is later arrested after being caught with the loot and mistaken for Grandma Dynamite.
"Fred El Terrifico": Pearl makes only a brief appearance in this episode. She has agreed to look after Pebbles and Bamm-Bamm while the Flintstones and Rubbles are on vacation in Rockapulco. As the car pulls away, Pearl yells "STOP" before telling Fred he has dirt on his upper lip (referring to Fred's moustache).
In her first four appearances on the show, Pearl was voiced by Verna Felton, who was at the time best known for her voice work in several Disney films including Lady and the Tramp and Alice in Wonderland. From "Fred El Terrifico" onwards, she is voiced by Janet Waldo.
In the 1994 live-action film, Pearl was portrayed by Elizabeth Taylor.
- She and Fred don’t have a good relationship.
- She has or had a wealthy life, probably is still quite wealthy.