

Word of God states they literally put it there to get up the nose of a particularly pushy film executive who seemed to hate everything about the film, so they put a random watermelon in to see if they could get a rise out of him, and when the scene raised no objections, they figured out of it that he'd stopped watching the production work and they were free to go as strange and wacky as they wanted. Big-Lipped Alligator Moment: Why is there a watermelon there? Reno promises to tell him why, and never does.It also didn't help that Buckaroo Banzai was almost totally eclipsed by the then rising cult status of Doctor Who, The Hitchhiker's Guide to the Galaxy (1981), Red Dwarf, the Cyberpunk genre, and "Japanimation", all of which offered refreshing stylistic differences compared to typical American sci-fi/comics at the time.
BACKAROO BONSAI POSTER MOVIE
This is a movie that was specifically designed to be a Box Office Bomb whose hyper-niche appeal would eventually earn it a cult following through TV and home video. With heavy promotion at Star Trek conventions (ironically, Star Trek III: The Search for Spock beat it at the box office).

It also includes heavy Shout-Out to a lot of science fiction tropes that were already out of vogue long before the film was made (the titular character was literally a spoof of the typical "Heinlein Hero"). It was designed specifically to appeal to fans of sci-fi and comic books back before such things had the broad appeal they have now.
