Betsy"Mama"Krabs is the widow of the deceased Victor Krabs, the mother of Eugene H. Krabs, and the maternal grandmother of Pearl Krabs (although they have never been seen onscreen with each other). The episodes that have featured her have shown her to be very strict and no-nonsense. She is voiced by Paul Tibbitt (despite being a male voice actor) in her first two appearances, and by Sirena Irwin in all her later appearances.
In the same manner by which all octopodes on the show are modeled after Squidward, Mama Krabs is very similar to her son in terms of appearance. She has wrinkly light red skin, wears a purple dress (She sported a blue one in "Mid-Life Crustacean") and large blue glasses, and has a small patch of fluffy white hair. In "Friend or Foe," she looks no younger than in her other appearances. In "Sailor Mouth," she had a slightly male voice. In "Enemy In-Law," Mrs. Krabs is also known to be greedy, like her son, for when Mr. Krabs greets her, he usually asks her how much money she wants.
Victor Krabs either died between 1947 and the events of Friend or Foe or Victor divorced Betsy between those dates. If he divorced Betsy and their daughter was not an adult by that point, then he took their daughter with him.
In "Stanley S. SquarePants," in a scene, three nephews of Mr. Krabs are shown, who are a parody of Disney's Huey, Dewey and Louie. This would imply that Betsy Krabs has another son or daughter.
In the episode entitled "Grandpappy the Pirate" Mr. Krabs' Grandad says he is his only grandson, implying that Betsy's other child may be a girl.
In "Enemy In-Law," Plankton falls in love with her due to her grandmotherly appearance.
Mama Krabs has a laugh strikingly similar to Popeye the Sailor Man.
In the episodes "Sailor Mouth" and "Mid-Life Crustacean" Betsy Krabs' voice sounds like an old woman version of Mr. Krabs (while played by Tibbitt), while in the episode "Enemy In-Law," "Spongicus," Friend or Foe," etc. she had a younger Scottish voice (while portrayed by Irwin).
It is shown in the episode "Enemy In-Law" she has large muscles after she learns that Plankton tricked her to get the Krabby Patty secret formula.
She appeared in the book, Mother Knows Best with a different appearance. She wore a pink dress, lipstick, and no glasses and looked about the same age as her son.
She wanted to see SpongeBob and Patrick get mauled by the lionfish in "Spongicus." She even states that she "wants to see some body parts!"
In "Enemy In-Law," at the end she falls in love with Plankton's giant robot but it is unknown if they got in a relationship.