Move over, Pennywise: Joaquin Phoenix is the scariest clown in 'Joker' trailer

How does an ordinary man become Batman's greatest nemesis? Judging from the first teaser for Todd Phillips's Joker, it takes a failed stand-up comedy career, some mommy issues, lots of clown makeup, and a killer smile. The two-and-half-minute trailer teases Joaquin Phoenix's transition from Arthur Fleck, an aspiring entertainer who's trying to work through his issues in therapy, to Joker, an unhinged lunatic who takes out his issues by terrorizing the citizens of Gotham. Watch it above.

The trailer lends credence to reports that Joker is inspired by The Killing Joke, Alan Moore's controversial 1988 graphic novel (which previous Batman movie directors Tim Burton and Christopher Nolan have also cited as an influence, and which itself was adapted into a 2016 animated film). The Killing Joke established Fleck's back story as a desperately unahppy man who tries to support his pregnant wife with a stand-up comedy career, but turns to crime to supplement his income. When tragedy strikes and a heist goes very wrong, Fleck goes insane, and the Clown Price of Crime is born.

However, the Joker trailer includes plenty of intriguing details not in Moore's story, including an odd mother-son dynamic (Arthur is shown bathing his possibly sick mother, Penny, played by Frances Conroy), a prior association with Arkham Asylum, and a mystery woman who could be a love interest (Zazie Beetz). Even if Phillips started with The Killing Joke, his Joker origin story has definitely taken on a life of its own.

Along with the teaser, Warner Bros. has released the first poster for the film, featuring Phoenix in full makeup and the tagline "Put on a Happy Face" (a song that, of course, plays ironically over the trailer).

Phoenix is the fourth Oscar-caliber actor to put an original cinematic spin on the iconic role, after Jack Nicholson (Batman, 1989), Heath Ledger (The Dark Knight, 2008) and Jared Leto (Suicide Squad, 2016). Social media reactions show that a few Joker skeptics have already been won over.

Joker opens in theaters on Oct. 4.

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