For those who have seen it, it's hard to forget the unsettling opening scene of Todd Phillips's Oscar-winning film Joker.
But there could be an Easter egg in those first few minutes that many of us did not catch.
As a radio crackles in the background, the camera moves in on Arthur Fleck (Joaquin Phoenix) as the comedian, sitting at a dressing table as he applies his clown face paint.
Now, eagle-eyed viewers have spotted that right there, in the mirror in front of Fleck, the reflection of the overhead lamps resembles Batman’s cape, pointy ears and all.
It was first spotted by Reddit user Valconix1. If correct, it could be an ingenious reference to the Joker's nemesis in the film. Bruce Wayne does make an appearance in Joker, but as a young boy, with his destiny as the caped crusader still some years ahead of him.
But it is likely that the image in the mirror, however closely it resembles Batman, is merely a coincidence.
In an interview with film website Collider in October, Phillips explicitly said he didn't do Easter eggs. "Any Easter eggs anybody finds is a mistake. I don't understand," he said.
This was in response to another subtle detail that fans noticed in the film, namely how several clocks were set to 11:11, a number some see as a symbol of the soul’s reawakening.
Halfway through the film, Fleck smashes a clock that reads 11:11, and some fans believe that that is when his transformation to the Joker persona is completed.
Another theory is that the events in Joker are set in Bizarro World – a fictional planet in the DC Universe, which contains warped versions of the DC Comics characters, including Superman and Batman.
But probably none of that applies to Joker. If anything, Phillips wants fans to take the work in isolation, and seems to be taken by surprise at the theories fans have been coming up with.
“It’s a coincidence,” Phillips once said of the clock theory. “No, I mean, I don’t know. I think it’s a coincidence. That’s two times. Is there another time? No, no that’s just interesting.”
Joker defied box office expectations upon its release, grossing more than $1 billion (Dh3.67bn) worldwide. The film was also an Academy Award favourite this year, with 11 nominations and two wins. Phoenix won the Best Actor award for his role as the manic supervillain, while the composer Hildur Gudnadottir received hers for Best Original Score.
A sequel is reportedly in the works. However, not much is known about the project at this point, except that Phoenix is set to reprise his role, and Phillips is set to direct.