In the "Batman" television series, Robin was known to use a catchphrase of "Holy ..." followed by a noun, and this would be done repetitively for comedic effect to announce an intense situation in the plot. These lines were recited by Burt Ward, the actor who played Robin, and since then the catchphrase has become a part of pop culture.
The catchphrase was repeated constantly throughout the series as a form of camp humor. A fan-made directory exists which actually compiled every single variation of the line from the television series, including lines like "Holy Smokes," "Holy Bat Trap," "Holy Detonator" and "Holy Jackpot." The lines often used alliteration and assonance for comedic appeal, like "Holy Hi-fi," "Holy Hoaxes," "Holy Headache," "Holy Homework" and "Holy Hoodwink." This catchphrase became so much a part of the Batman culture that it even appeared in the "Batman Forever" movie, where Robin quips "Holy rusted metal." This was obviously meant as an in-joke with fans who were aware of Robin's catchphrase from the classic television series. The catchphrase has become part of the American vernacular, especially in the realm of comic book culture.