Musk' film is almost four hours long, engrossing and terrifying. What to know.

Elon Musk’s upcoming documentary “Musk,” by filmmaker Alex Gibney, runs 3 hours and 45 minutes plus a 10-minute intermission and reaches theaters Oct. 16. The film has already drawn controversy for portraying Musk as an “emotionally unstable grifter,” with power and influence that Gibney says are “extremely dangerous to world democracy.” Speaking at the Venice Film Fest, Gibney framed Musk’s rise as an old pattern seen in earlier cases, citing inflated stock as a recurring theme. Musk has disputed the portrayal in social media posts and, through attorney Alex Spiro, threatened a defamation suit over a text exchange shown in the movie.