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During season three, each episode ended with a teaser featuring the next episode's villain.
When Burgess Meredith was cast as the Penguin, he hadn't smoked in 20 years. He came up with the Penguin's distinctive squawk because the cigarettes irritated his throat. The Penguin's waddle was another improvisation; Meredith found it difficult to stand and walk straight while wearing the rubber padded fat suit that was part of his costume.
After ABC cancelled the series, the producers waited to see if anyone else would pick it up, then bulldozed the Batcave set when it appeared nobody would. Two weeks later, NBC offered to pick it up, unaware that the set had already been dismantled; unwilling to invest in the high cost of rebuilding the entire set, NBC ultimately declined to acquire the series.
Before going on the air, this show received the worst audience test scores in the history of ABC. It only went on the air because so much money had already been invested in it.
Robin uses 352 "Holy" phrases, from "Holy Agility" to "Holy Zorro."
Mr. Zero was renamed Mr. Freeze for this series. The name change eventually made its way into the comics as well.