Joni is similar in appearance to Johnny. She has blonde hair with orange highlights, also known as "flaming hair." She has blue eyes and pink lips. She wears a white shirt with a hazard sign on it, a blue jacket, green cargos, white shoes with black laces, and a black watch. Her best friend is a genetically altered female dog named Dutchy, similar to Johnny's friend Dukey.
Also, in the episode Johnny Alternative she seemed to like or have a crush on Johnny. He first thought it was disgusting, then later on he ended up almost kissing her.
- Unlike Johnny, she is a bad shot.
- Both she and Johnny can climb trees well and often take things from their siblings.
- She and Dutchy don't know how to use the weapons they use unlike Johnny.
- Johnny saved her from turning into a cat by jumping in front of the blast from a cat ray fired by Mrs. Mittens.
- She gives her brothers coupons like Johnny for free experiment tests.
- She and Johhny have similar hand writing as shown when her brother holds up a free test coupon.