We've seen some pretty wild takes on Batman's nemesis the Joker over the years, from Cesar Romero's uber-camp portrayal in the 1960s TV series, through to more sinister incarnations courtesy of Jack Nicholson and the late Heath Ledger.
We've even seen a more complex approach, thanks to Joaquin Phoenix's star turn in 2019's controversial smash hit Joker - but regardless of who's donning the Clown Prince of Crime's signature colours, it seems there are some rules that always have to be followed.
The folks of Looper have put together a short list explaining the core details that every self-respecting Joker actor should bear in mind.
So whether you prefer the character as an agent of chaos, or simply dancing with the devil in the pale moonlight, here's what they have to do...
1. Get the look right
OK, we all know this one. The Joker wears purple clothes and has green hair, and every actor to play him has managed to get this right in at least one scene.
Other villains in the Batman universe may have favoured less colourful outfits in more recent films - Bane, Scarecrow, the plethora of gangsters keeping the franchise tied to its noir roots - but the purple and green combo is non-negotiable. Hey, if it works...
2. Sense of humour
He's called the Joker for a reason, right? It's not just a clever name. And that's why his warped sense of humour is a must for all cinematic depictions.
Cesar Romero cackled away interminably, in nightmarishly pantomime fashion. Heath Ledger's version made a pencil 'disappear' as a grisly visual punchline. Even Joaquin Phoenix's bleak interpretation was based on a tragic figure who wanted to be a stand-up comedian. It's part of what sells the character.
3. His signature laugh
Of course, not only is the Joker up for a laugh - even if it usually turns out to be pretty horrifying - but he also has a thoroughly recognisable laugh. It usually appears at the character's darkest moments, with a frequency that has seen that signature chuckle regularly described as 'maniacal'.
Joker director Todd Phillips repositioned the laugh as a medical condition, adding an extra dimension to his tragic vision of the supervillain. In most versions, though, it's another chilling reminder of his unhinged nature.
4. He's Batman's nemesis
Superman has Lex Luthor, Wolverine has Sabretooth, Spider-Man has Venom. Every superhero needs a powerful arch-enemy, and Batman and the Joker are as good as it gets.
While the Caped Crusader dresses up as a bat every night on an endless quest to avenge the murder of his parents, trying to restore some sense of justice, the Joker prefers evil for its own sake. He's a wild card and Batman's opposite in almost every sense.
5. When we say 'nemesis', we mean it's personal
So about that arch-enemy thing... we're not just talking 'bad guy steals a bunch of mcguffins and hurts a few people'. Batman always has a personal stake in his mission to bring the Joker to justice, although it varies from movie to movie.
In Tim Burton's 1989 movie Batman, Jack Nicholson's Joker is revealed to be the man who murdered Bruce Wayne's parents, prompting him to become the Dark Knight in the first place. In 2008's The Dark Knight, he kills the love of Bruce's life. There's always something going on.
6. He's going to steal the show
Batman may be the hero of the movies, but the Joker's flamboyant nature means all eyes are on him whenever he's on camera. The bright-coloured costume helps, sure, but whoever plays the villain is going to have to absolutely command every scene.
Think about Jared Leto's fearsome interrogation scene in Suicide Squad, Heath Ledger seizing control of Gotham City's mob bosses in The Dark Knight, or Jack Nicholson dancing around the museum while Prince plays in the background. Iconic scenes, all absolutely owned by the Joker.
7. Constantly evolving
Part of the character's sinister appeal is that he's relatively open to interpretation, which means each portrayal is going to be different to the last. It means each actor has the opportunity to redefine the Joker once more, in the face of Batman being a more reliable role.
After all, when you think about the various interpretations, it's all about the differences, isn't it? The Joker's ever-changing origin story and wildly differing depictions give him a sense of mystery that mean you never know what to expect from movie to movie.
8. He's going to make quite an entrance
Every time a movie sees the Joker appears on screen for the first time, it's a memorable moment. Who could forget the bank heist scene in The Dark Knight? Or the moment the bandages are pulled away from Jack Napier's face in Tim Burton's Batman to complete his evolution from mobster to supervillain?
As we mentioned before, he's a scene-stealer. He upstages everyone, and any Batman director knows they're going to have to pull off a grand introduction for the franchise's most notorious villain.
9. The Joker is pretty damn scary
It'd be one thing if the Joker was just wisecracking and making things generally uncomfortable for... well, everyone around him. But he's also got to be terrifying. OK, the laugh helps, as does his apparently motiveless evilness. There's got to be more than that though.
The Joker is unpredictable, dangerous and utterly unhinged. Add all this together, and it's ripe for an utterly compelling villain who's going to leave audiences chilled to the bone. If you're not unsettled by his presence, something's gone wrong somewhere.
10. He can't actually kill Batman
It wouldn't be much of a movie if he did.Featured Image Credit: Warner Bros.