First, some 14 year old Dutch girl tweeted a terroristic threat to American Airlines.
She got 30K followers as a result, which naturally lead to copycats.
Yesterday, some "Performance Artist" from a Massachusetts Art School left a backpack (reportedly containing a pressure cooker filled with confetti) at the site of last year's Boston Marathon Bombing. Here's some info about him thanks to the guys at Uproxx.com.
Not sure if this guy is insane, or just wants you to think so. Here's a piece of his "performance art". You be the judge!