Because all Anti-Fairies are the opposite of their fairy counterparts, instead of being smart and hot-tempered like Wanda, Anti-Wanda is dimwitted and always happy, just like Cosmo. Her IQ is so low that she doesn't know how to eat properly, and as such she eats with her feet (instead of her hands like normal people), and much like Cosmo, she foils plans without knowing what's going on (Anti-Wanda may also be even more stupid than Cosmo as shown in some episodes). She has a few missing teeth and speaks in a hillbilly and county Southern accent.
Anti-Wanda resembles Wanda, but her color scheme is dark blue and black. She has bat wings and a black crown like all Anti-Fairies. She has pink eyes like Wanda, although she has missing teeth and the rest of her teeth are crooked. She also does not wear any shoes because she uses her feet to eat sandwiches.
Anti-Wanda speaks in a southern hillbilly accent and eats with her feet. Her stupidity is often the cause of trouble for Timmy and her husband. It is unclear whether or not Anti-Wanda is a real threat, because usually she is just following her husband's lead. She is not the complete opposite of Wanda, because both love their children.
In April when bad luck happens, the Anti-Fairies were released to do the bad luck, Anti-Wanda was still trapped until Timmy and Cosmo wished them all out. Without knowing that they caused trouble, all of the Anti-Fairies were released to cause havoc. But they were eventually sent back when Timmy tricked them into going to Fairy World. They were now trapped in a maximum security prison where the worst villains of all time were kept.
The prison was wish-proof, so no one could wish them out. Timmy made a plan to break Anti-Cosmo out, but every one of them failed, and one reason was because of Anti-Wanda's stupidity. Despite this Timmy and his godparents were able to get Anti-Cosmo out and were able to do the Fagiggly Gland surgery for Cosmo. Later she broke out thanks to Professor Calamitous. She was recaptured however thanks to Jimmy's modified Hyper Cube. After that she is usually seen in Anti-Fairy World with her husband and the other Anti-Fairies.
In the "Anti-Poof", Anti-Wanda gives birth to her and Anti-Cosmo's son, Foop. Later on, Foop betrays the other Anti-Fairies by turning Anti-Fairy World into a happy and colorful place. Despite this betrayal, when Foop is defeated Anti-Wanda still loves her son and shoves a bottle in his mouth when he was crying. Later on, she and Anti-Cosmo brought a cake with a metal file tool stuck in it so that he could try escape from his "maximum security time out" at Abracatraz.