See this earlier post for more background on THUNDARR.
"City of Evil" is a second season episode, opening with Thundarr and company chasing an evil wizard to retrieve a guantlet of power. The gauntlet is the most Kirbyesque element of the episode, with one close-up that seems to be taken straight from Kirby's design. I'll try to get a screen capture of it. Anyway, they defeat the wizard and return the gauntlet to its rightful owner, but the wizard then finds a shrunken city full of scientists and plans to use the power of the gauntlet to restore the city and rule the world. Another good Kirbyesque element in the episode shows up later when the shrunken residents of the city attack in tiny flying sleds.
Fun episode, with some clever ideas and neat visuals.