She is shaped like a thick light green stack of money with a matching pair of arms and legs. She has a a dark green band looped around her with a dollar sign in the middle, designed like a belt. She has hot pink lips and oval-shaped green eyes. Her hair is a smaller stack of money curled to form bangs. On the right of her head, she has a red bow with beige polka dots.
Plankton first gets the idea for Cashina when he tells Mr. Krabs he should marry money if he loves it so much, and Krabs says he would if he could. Later that night, Mr. Krabs hears crying, which is coming from a bus stop near the Krusty Krab. He walks over to investigate and finds a stack of money with a face and limbs, wearing lipstick and a bow. Mr. Krabs, unaware that it is a robot controlled by Plankton, is instantly in love with her. Apparently, her date, who is supposed to bring him to the bank, stood him up. Mr. Krabs hands her a tissue and she says her name is Cashina. Since the latter likes him back, they agree to go on a date together.
At the restaurant, they share spaghetti and kiss afterwards (a la Lady and the Tramp). The kiss somehow electrocutes Mr. Krabs. After that, he invites Cashina to his house. Pearl does not like her that much at first, but warms up to her after discovering they share many of the same interests. Krabs then proposes to Cashina and she accepts.
After the wedding, where Mr. Krabs gets electrocuted again, they spend their honeymoon at the Honeymoon Hotel. Cashina asks Krabs to unlock his heart for her and tell her the secret Krabby Patty formula since they are married now. Although he wants to tell her the formula, Mr. Krabs gets choked up and starts sweating. He tries to tell her the secret formula anyway, but a tear falls from his eye into Cashina's mouth and onto Plankton's control panel, causing her to short circuit and then explode.
After Krabs finds out that Cashina is actually Plankton, he is very angry and upset at him. Plankton then goes away, leaving Mr. Krabs to mourn the "death" of his "wife" by himself.