She appears in five episodes, usually playing a small cameo role. She was voiced by Paul Tibbitt in her first two appearances and by Sirena Irwin in "Enemy In-Law," "Friend or Foe," and "Spongicus." The episode "Enemy In-Law" is her only major role in the series. She has not made a physical appearance since her brief cameo in "Spongicus," but was imagined in a dream sequence in "Lame and Fortune."
In the same manner, by which most octopuses 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.
The two had two children, Eugene Harold Krabs, who was born on November 30, 1942, and an unnamed daughter, born either before or after Eugene's birth.
At some point, her father-in-law took custody of her son while he was an infant. Though the events of "Friend or Foe", Eugene is seen living with her again. Victor was not seen and presumably divorced Betsy between 1947, since he appears alive in “Senior Discount”. It can be guessed that he took their daughter with him if she was not an adult by that point.
In the episodes "Sailor Mouth" and "Mid-Life Crustacean" Betsy's 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 has 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 has a different appearance in the book Mother Knows Best. She wears a pink dress, lipstick, and no glasses, and looks about the same age as her son.
She wants to see SpongeBob and Patrick get mauled by the lionfish in "Spongicus." She even states that she "wants to see some body parts!" This shows she likes violence.
In "Enemy In-Law," in the end, she falls in love with Plankton's giant robot, but it is unknown if they got in a relationship.