While it became popular after it was used in Red vs. Blue, headlight fluid doesn't originate from the series. It was invented during a prank call made by Detroit’s Channel 955 radio DJ Spike which was originally featured as a segment on the AM radio show Mojo in the Morning and subsequently released on a compilation CD in May 2001. Titled “Clueless Auto Repair,” the call consisted of a person posing as a mechanic advising a woman on the state of her automobile repairs. At some point, Rooster Teeth learned of the prank call and applied the idea to the web series.