Egghead would return three times in the third season with his new partner and love interest Olga, Queen of the Cossacks (Anne Baxter), an exile from Bessarovia. The first two third-season appearances, "The Ogg and I" and "How to Hatch a Dinosaur", were actually filmed as one multi-part story, but split into two separate stories (Season 3 episodes 8 and 9) prior to airing. In "How to Hatch a Dinosaur," Egghead and Olga plan to hatch an egg of a "Neosaurus" and later to try to feed Robin and Batgirl to it. It does not work, however, and the "Neosaurus" - actually Batman in disguise - advances toward Egghead and Olga, causing them to surrender to the police.