Whether you call it “K2” or “Spice,” synthetic marijuana is keeping local and national authorities on their toes.

In late September, the New York City Police Department seized $10 million worth of the street drug. A joint effort between local police, the Drug Enforcement Administration and the Department of Homeland Security, the East Bronx bust was part of a larger effort to quell K2’s growing influence in the New York metropolitan area.

Acting quickly, the New York City Council passed new legislation that imposes “penalties for the manufacture, distribution or sale of synthetic cannabinoids and synthetic marijuana” by a unanimous vote on Sept. 30—just days after the East Bronx seizure.

“This is a scourge on our society, affecting the most disadvantaged neighborhoods and our most challenged citizens,” NYPD Commissioner William J. Bratton said in a statement released one week before the bust. “It affects teenagers in public housing, homeless in the city shelter system, and it’s quite literally flooding our streets.”

So what exactly makes K2 so dangerous? What are authorities doing to control the drug’s circulation? And will their efforts even work?