Betsy "Mama" Krabs is the widow of the late Victor Krabs. She is the mother of Eugene Krabs, and the paternal 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 male voice) in her first two appearances, and by Sirena Irwin in all later appearances.
In the same manner by which all octopi on the show are modeled after Squidward, Mama Krabs is very similar to her son in terms of appearance. She has wrinkly 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. She is thought to be around 90 years old. In Enemy In-Law, Mrs. Krabs is also known to be greedy, like her son, for when Mr. Krabs greets her, he asks how much money she wants.
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 it that Betsy's other child is a female.
In Enemy In-Law , Plankton falls in love with her due to her grandmotherly appearance.
A portrait of her married to her husband is shown in the episode "Mid-Life Crustacean " when she is disciplining Mr. Krabs.
She was evidently a poor woman in the mid-to late 1950s, as she had no money to buy Eugene clothes. Old Man Jenkins spared some car-washing rags from the trash can to fix him what to wear. However, she still wore kind-of formal clothes.
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 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.
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.
In Enemy In-Law, Mrs. Krabs calls Mr. Krabs her favorite son, implying that she had more than one son.
"Am I really that pretty?" (Enemy In-Law)
I just wanted to see my favorite son? (Enemy In-Law)
How did you know I wanted a hat? Have you been spying on me? (Enemy In-Law)
Hello Eugene? (Enemy In-Law)
Well, I did see the prettiest hat in town today? (Enemy In-Law)
Oh, you're that giant robot? (Enemy In-Law)
"You should all be ashamed!" (Sailor Mouth)
"I think you scallywags have earned a glass of lemonade. Ag-gah-gah-gah!" (Sailor Mouth)
"If you're going to talk like sailors, then you're going to work like sailors!" (Sailor Mouth)
"Boring! I want to see some body parts!" (Spongicus)
"Eugene? What are you doing with my bloomers?" (Mid-Life Crustacean)
"Oh dear!, My poor old heart!" (Sailor Mouth)
Boring I Want To See Some Body Parts? ! (Spongicus)
"The formula?! Is THAT what this is all about?!" (To Plankton, in Enemy In-Law)
YOW! My (old car horn) foot! (Sailor Mouth)
What? It's Old Man Jenkins in his jalopy. (Sailor Mouth, after being scolded by Mr. Krabs)
Eugene, Lights out! (Mid-Life Crustacean)
Eugene, you put me boyfriend down this instant! (To her son, in Enemy In-Law)
Come, Plankton, I'm sorry me son has to spoil our romantic evening. (To Plankton, in Enemy In-Law)
I'm right here! (Spongicus)
Go to your room, Mister! You're grounded for the rest of the night! (Mid-Life Crustacean)
Well, how about the Krusty Krab? Tonight at 8:00? (Enemy In-Law)
Isn't it nice, Eugene? It's just the one I wanted? (Enemy In-Law)
Where did you get that old thing? (Enemy In-Law)
You can take this one back to the trash heap? (Enemy In-Law)
Thank ye for your concern for my finances, but me new boyfriend bought me this hat? (Enemy In-Law)
I don't know. I'm meeting him here, tonight? (Enemy In-Law)
Eugene!! What Did I Tell Ye About Interferin' In Me Life? (Enemy In-Law)
For your information, Eugene, he hasn't asked me once about the formula. I doubt that he even knows that I know it!! (Enemy In-Law)
I forbid ye to interfere in me private business. Go to your office, now! (Enemy In-Law)
Oh Sheldon. (Enemy In-Law)
There you go, son. Your outfit's all finished. It's a good thing Old Man Jenkins was kind enough to spare his last washcloth. (Friend or-Foe)