The end-credits scene joke in Birds of Prey (And the Fantabulous Emancipation of One Harley Quinn) is a reference to the Harley Quinn animated series on DC Universe. Though featuring several of DC Comics highest profile heroines from Huntress to Black Canary, Harley Quinn is the true centerpiece of Birds of Prey for better or worse. As of now this is the closest thing audiences have gotten to a movie built around the character, but she has been busy in all media in recent months. She currently has her own adult animated show on the DC Universe streaming service, which is slyly referenced at the end of the film in the form of one of its running Batman gags.

In typical superhero movie fashion, audiences expect something extra once the credits roll. Although Birds of Prey did not have an end credits "scene" per se, there was a little treat for fans of her TV series. As the credits concluded and the Warner Bros. logo appeared on the screen, Harley's voice can be heard saying "Are you dummies still sittin' there? Fine. Since you stuck it out this long I'll tell you a super duper secret secret. You can't tell anyone. Okay. Did you know that Batman f-." The audio is cut before she can finish, leaving committed moviegoers largely confused, that is if they were not familiar with the joke she was about to make.

Related: How Birds of Prey Sets Up A Proper Harley Quinn Sequel

Fans of the show will know that Harley has come into contact with the Dark Knight more than once. Her tireless crusade to step out from her ex-boyfriend The Joker's shadow and impress the Legion of Doom in order to be seen as a real villain is the crux of the series. Unsurprisingly her evildoing has put her in the Caped Crusader's sights countless times. In her uniquely obnoxious fashion, she is always ready to fire back at him with a quip, one of the most common being that he "F**ks bats." Clearly Batman does not share a bed with flying rodents, yet Harley often tosses the line out there in an attempt to get under his skin.

Harley Quinn DC Universe Batman and Harley

Though she couldn't get the line fully out, the DC Extended Universe version of Dr. Harleen Quinzel appears to share this belief, despite her ironic Bruce Wayne crush. DC has been careful to keep all of their properties separate, rarely acknowledging that there are other continuities out there. Though they have gone back on this practice in recent months, for example during the CW's Crisis On Infinite Earths event, it is still new ground for them.

For the Birds of Prey's post-credits scene to make reference to this relatively niche program is a neat Easter egg for devout fans of either. Who knows if there is to be any more personality overlap between these two incarnations of Harley Quinn, but at least there is now some kind of effort made to ensure the character is consistent across all formats. Most specifically in regards to Batman's bedroom habits.

More: Birds of Prey Sets Up The Harley Quinn/Poison Ivy Romance For Future Movies

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