Warner Bros. Pictures just released a disturbing teaser trailer for the new upcoming movie Joker. Starring Joaquin Phoenix, the trailer reveals a little bit about how a man eventually morphs into a killer.

There are a lot of movies that tell the story of the Gotham City characters, from 1966's The Batman Series to 2016's Suicide Squad. This film in particular focuses on the life of The Joker and how he turned into a murderous, psychotic clown. Themes of bullying, mental illness and violence are all present in the disturbing two-minute video. Watch the trailer below.

There's a long line of actors who have portrayed the character in live-action films, starting with Cesar Romero in 1966's Batman: The Movie, followed by Jack Nicholson's 1989 performance in Batman. The late Heath Ledger actually went as far as isolating himself in a hotel room for weeks in order to adapt to the character's personality for 2008's The Dark Knight, which many regard as his all-time best acting performance.

30 Seconds to Mars' Jared Leto played the villain in 2016's Suicide Squad, though there was some controversy surrounding how much of the clown's screen time was left out of the final movie.

Needless to say, Joaquin Phoenix has some pretty big shoes to fill. Joker comes out Oct. 4.

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