Batman live-action series
Egghead was introduced in the second season two-parter, "An Egg Grows in Gotham" and "The Yegg Foes in Gotham," where he schemed with Chief Screaming Chicken of the Mohican Indian tribe to revert control of Gotham City to the Chief's people. In return, Egghead would also govern the city and enable the criminal underground to run amok. Their scheme was foiled by Batman and Robin.
Egghead would return three times in the third season with his new partner and love interest, Olga, Queen of the Cossacks, in 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's plan was to hatch an egg of a Neosaurus and later to try to feed Robin and Batgirl to it. It didn't work and the Neosaurus advanced toward Egghead and Olga causing them to surrender to the police as the Neosaurus was actually Batman in disguise.
The final season three appearance was in episode 15 "The Ogg Couple" where Egghead and Olga steal the Sword Of Bulbul and The Egg Of Ogg.
In "The Entrancing Dr. Cassandra," Egghead (alongside Joker, Penguin, Riddler, Catwoman, and King Tut) was freed from prison by Dr. Cassandra Spellcraft and her husband Cabala, but this brief appearance was by a stand-in. Dr. Cassandra Spellcraft promised Egghead control over the poultry farms when she took over Gotham City even giving him and the other villains her camouflage pills to assist in their crime spree.
Egghead was one of only two Batman 1960s series villains to deduce Batman's secret identity (and the only one to do so through deductive reasoning instead of trickery). Reasoning that the enormous "egg-spense" involved would point to only one of three Gotham City millionaires who would be of the right age as Batman and deducing that two could not be the Caped Crusader (one has a French accent, which Batman does not have, and the other is left-handed, whereas Batman is right-handed), he concluded that the last, Bruce Wayne, must be Batman.