Manhunter to Green Lantern: "Sit on it!" (Justice League of America #141, 1977).
In 1977, Happy Days was the number-one TV show in America for the third year in a row. Fonzie merchandise was everywhere, and people of all ages loved quoting “the Fonz.” I can’t help but wonder whether having an alien use Arthur Fonzarelli’s catchphrase was an unconscious choice by this comic book's writer or an intentional joke. The phrase was so ubiquitous in 1977, audiences may not have even noticed it, but forty years later, it stands out as a remarkably strange thing for an alien to say.
