She first appeared in the "Super DuckTales" special as the receptionist in Scrooge McDuck's bean factory. Fenton wanted to invite her out but didn't dare to do it. Near the end of the special when he finally does; she answers that she wanted to go out with him when he was a bean counter, but he never asked her. From then on, they began dating.
It is later revealed that Gandra studied advanced robotics in school, enabling her to control a gigantic mantis mecha. She explained her eclectic choice with "The nail-polish class was full..."
Darkwing Duck comic
Gandra Dee's only appearance in any comic book was in the DuckTales/Darkwing Duck crossover story arc "Dangerous Currency". However, since the story was never approved by Disney, it is considered non-canon.
Gandra Dee appears in Season 2 of DuckTales. She is portrayed as a grunge style scientist who doesn't kiss up to millionaires and does her own thing. In "The Dangerous Chemistry of Gandra Dee!", at first, she and Fenton discussing their professions who want him to show his lab they stared having common things together, later he learned that she a spy for Mark Beaks to learn Gizmoduck's passcode for her nano serum too work after he breaks in, he has recorded Gizmoduck's catchphrase because having drunk an overdose of nano serum he grows his muscle mass, during the fight in the lab, Gandra shocks Gizmoduck's suit and shuts it down, giving Mega Beaks time to kidnap Huey and Webby, but she soon finds herself genuinely interested in Fenton and eventually helps him defeat Beaks she tries shocks him with her nanobots but the nanobots will not work on his outer body, so Fenton distracts as him and Gandra charges the Fentonium ball and Fenton knocks into the insides of Beaks; The shock shorts out the nanotech turns him to normal, she disappears afterward, Fenton finds she has given him the equation to stabilizing Fentonium. Later in "Moonvasion!", it's revealed she's an agent of F.O.W.L. who plans to end Clan McDuck.
In Season 3, where "Challenge of the Senior Junior Woodchucks!" depicts the mosquito that was bothering Donald turns revealed to be a F.O.W.L. robot, Gandra Dee states that the Duck family have found the hidden journal of Isabella Finch. In between the events of "Escape from the ImpossiBin!" and "The Split Sword of Swanstantine!", where the McDuck family are now aware that Gandra Dee is a F.O.W.L. agent. However, in "Beaks in the Shell!", it is revealed that she was merely using F.O.W.L.'S mainframe to work on a virtual reality project with Fenton (with whom Gandra has entered an official relationship with) and intended to leave F.O.W.L. once it was completed. Unfortunately, Bradford Buzzard found out and had Gandra locked away in the lost library at the end of the episode.
- Her name is a reference to actress Sandra Dee.