Warning: This article contains SPOILERS for Joker.
The future of Bruce Wayne is one of the big Martha Wayne (Carrie Louise Putrello): they are murdered in an alley after watching Zorro The Gay Blade. Could this version of Zorro inspire young Bruce (Dante Pereira-Olson) to become Rainbow Batman?
In set in 1981, the same year Zorro The Gay Blade was released. Starring George Hamilton in the dual-title role, the plot of Zorro The Gay Blade is about an injured Don Diego Vega becoming unable to fight evil as Zorro. Enter his flamboyantly gay twin brother Ramón, aka Bunny Wigglesworth, who assumes the mantle of Zorro but he uses a whip instead of a sword and dresses in different, garishly-colored Zorro costumes. This is very similar, in effect, to Rainbow Batman.
If Joker's Bruce Wayne grows up to be The Batman (for now, at least), it's logical to assume Batman's future in Joker's universe unfolds similarly to other Batman continuities, like the Dark Knight of the Tim Burton and Joel Schumacher films did.
Rainbow Batman is a strange footnote in the Dark Knight's history but it has curious parallels to Zorro The Gay Blade: In Detective Comics #241 (1957), Dick Grayson's arm is injured while he saves a young girl. Soon after, Bruce Wayne inexplicably changes the colors of Batman's costume, wearing a different, brightly colored Batsuit every night before finally donning a uniform made up of all of the colors of the rainbow at once. It was a totally absurd scheme by Batman but there was a method to his madness.
The reason Batman did this turned out to be a simple distraction; knowing that Dick's injury was publicly known, Bruce worried that criminals would notice that Robin had an identical arm injury and would deduce that Dick Grayson was Robin. Therefore, Batman wore ridiculous colors to keep the attention away from Robin and keep his secret identity safe. In Zorro The Gay Blade, Bunny changing Zorro's signature black look also successfully confused the Vega brothers' enemies and both stories are meant to be wacky comedies.
Despite being retconned by Batman: The Brave and the Bold. Whether this was intentional or not by Todd Phillips, changing Batman's origin by establishing Zorro The Gay Blade as the Zorro movie Joker's Bruce Wayne watched could set the orphaned child on the path to not just becoming Batman, but also the Rainbow Batman later in his future.
