Japanese Man Dressed as Joker Goes on Knifing Rampage on Train

A Japanese man dressed as the Joker went on a rampage with a knife while onboard a train in Tokyo -- and video of the passengers attempting to flee is absolutely terrifying.

Check out this wild footage from inside a subway car Sunday that was heading to the Shinjuku station ... where folks were running for their lives after a guy who's said to be just 24 years old started randomly stabbing people -- all while donning a Joker costume.

You can see passengers from one train car hopping to another in sheer panic, and then huddle up together on the opposite end ... obviously scared to death. It looks like a movie ... but it's as real as it gets.

Witnesses told police and local media that the man was brandishing a long knife smeared in what looked like blood -- something bystanders thought was a Halloween joke -- and then he started swinging it, successfully stabbing upwards of 10 people ... per reports.

He then began dousing the interior with a liquid of some sort ... and tried setting the train ablaze. That's why you're seeing all the smoke start to build up -- and why people were literally jumping out of windows to escape. All in all, cops say at least 17 people were hurt, to varying degrees.

The perp appears to have sat down after all the chaos ... and lit a cigarette with his legs crossed, seemingly taking in everything he'd just done. It's as eerie as it sounds. People from the outside filmed him through the door windows ... all he does he stare back and smoke.

It wasn't long before the cops showed up and arrested him on suspicion of attempted murder, among other charges. He didn't put up much of a fight either -- looks like the man cooperated with police and allowed himself to be taken into custody.

Cops say they don't have any clear motive just yet -- but we're sure this dude will get the grilling of his life to figure out why he did this.