News article here:
A man dressed in Batman’s Joker costume has been arrested for attempted murder after a knife and fire attack on a train in Tokyo, according to Japanese media, with at least 17 people reportedly injured and one in a serious condition after being stabbed.
Witnesses told national broadcaster NHK of the bloody attack which happened on Sunday, when the Japanese capital was full of Halloween revellers, many in costume.
Media reports said the perpetrator, aged in his 20s and wearing a green shirt and indigo suit, attacked people with a knife and started a fire on the train.
More at the link.
Wow. The article refers to two other recent attacks, one of which involved acid. Again, wow.