Not Betty is a waitress that works at the Diner.
Not Betty is a darkish orange fish with bushy, red-orange hair. She wears a lime green shirt that has a yellow collar. She also wears a lime green hat with a light yellow rim, black glasses, and a nametag. If one looks at the top left of her hair, it is shown that she has a pen sticking out of her hair.
She is seen working at Diner late at night when a customer asks her for a pen. SpongeBob then tells his story about how he lost his identity. After he finishes the story, "Betty" tells SpongeBob he managed to kill eleven minutes. SpongeBob looks at her name tag and calls her "Betty." She then tells him that she is not Betty, but she is wearing Betty's uniform as hers is in the dry-cleaners.
Her hair appearance is similar to Didi Pickles from the 1991 Nickelodeon cartoon series Rugrats.
When "Betty" tells SpongeBob that he successfully managed to waste eleven minutes, this time is the average length of a SpongeBob SquarePants episode.