K2

Dozens of climbers eager to reach the summit allegedly walked past the man after he was gravely injured in a fall.
Photos and video appear to show Kristin Harila and her team climbing over an injured porter while ascending the mountain rather than saving him.
At least 70 people have overdosed in a park in New Haven, Conn., after consuming synthetic marijuana known as K2, authorities say. But what exactly is K2 and why is it dangerous?