Dr. Gelee is a scientific mastermind who decided that mankind was too evil and destructive to live. He thus planned to eliminate humanity by freezing the planet while he and his henchmen remained safe in his remote mountain fortress. He was defeated by the girls in "The Iceman Cometh". He appears to have an interest in Clover (either romantic or sheer lust) as he chose her as his Ice Queen and created a throne for her to sit on. He is another villain to develop such an interest in Clover (another being the Black Knight) and one of several that has one for any of the Spies in general.
In "Ski Trip", Gelee escapes from Prison and stalks the girls to their school ski trip. Blaming Clover for his defeat, he concocts a diabolical plan to get revenge by kidnapping Clover and forcing her to play a game of chess against him. Unfortunately for him, Gelee mistakes Mandy for Clover because of her red ski suit, as it was the same colour as Clover's Catsuit. Nevertheless, he holds Mandy hostage and forces her to play chess, during which Mandy remarks that he isn't even good at it. At the end of the episode when he tries to zap the girls with a laser from a distance, the beam bounces off Mandy's award and hits the top of the hill, causing a snow avalanche that buries him. However a visually similar character appears in the background of several episodes involving WOOHP prisoners so he could have survived to be incarcerated again.
Dr. Gelee has a poor memory. In "Ski Trip" he thought Mandy was Clover because Mandy was wearing a red ski suit. He did not notice the different hair colors, voices, and faces.
Based on his appearance and motives, Gelee is a parody of the Batman supervillain Ra's al Ghul.