Well a real interesting one would be "Suicide Circle" (2002) by Sion Sono. Its really visceral.  54 Japanese schoolgirls commit mass suicide by jumping in front of  a train at rush hour. You will not be able to take your eyes off the screen in addition to thinking about this movie for days. I would have said 'Heathers' but thats an American film, but still darkly comic, nevetheless.