When Dr. Cassandra is initially handling the Alvino Ray Gun, she holds it backwards, but by the time she comes to use it on Batman, Robin and Batgirl she is using it the correct way!
King Tut appears as one of the 'arch-villains' of Gotham City, even though in a previous (two weeks before) episode 'I'll Be A Mummy's Uncle' King Tut returned to his life as a professor of Egyptology after a blow to his head that completely reformed him.
Cassandra: (talking to Batman on Commissioner Gordon's phone) Just zip you're lip while I lay the word on you, Batcat. I'm gonna put Gotham City in a trance and there's not a thing you or that junior birdman can do about it. (laughs an evilly)
Robin: (Robin looks at Batgirl) You know something, Batman?
Batman: What's that, Robin?
Robin: She looks very pretty when she's asleep.
Batman: I thought you might eventually notice that. That single statement indicates to me the first oncoming thrust of manhood, old chum.
Dr. Cassandra: You'd better watch out. I've got your number, Batman.
Batgirl: What about *my* number, Dr. Cassandra?
Dr. Cassandra: Other women's numbers don't interest me, Batgirl.
This episode has the largest number of recognizable bat-villains than any other prior episode.
This episode ran over-budget so the ending was re-written to place the bat-fight in darkness and save on expenses.
This was the final appearance of the late David Lewis as Warden Crichton.
Look carefully at the villains which Dr. Cassandra springs from prison in this episode, and you will notice that Cesar Romero, Frank Gorshin, Burgess Meredith, Vincent Price, Victor Buono, and Eartha Kitt are not in their regular roles! All were unavailable, so stunt doubles filled in for them.