A few years ago, an unfamiliar drug began to pop up at some of the stops frequented by the Relief Bus, a retrofitted school bus that provides services for the poor and homeless.

The drug was "everywhere," says Josiah Haken, who does outreach for the organization. "Parolees used it because there was no test. Homeless folks used it because it was cheap. And everyone else used it because it was new," Haken wrote in a text message.

This was K2, also known as spice or synthetic marijuana, a substance with un-marijuana-like effects usually made from plant materials sprayed with different chemicals.

The word commonly used to describe the drug’s users is “zombies”; this transformation was on display Monday between Bed-Stuy and Bushwick where 33 people were hospitalized due to behavior often associated with using the drug. The non-uniform nature of the drug makes it difficult to know for sure, but a police spokesman said the hospitalizations are believed to be from a bad batch of the drug.

The hotspots

Scenes like that in Brooklyn, with K2 users stumbling around, passed out on the ground or hardly conscious, aren’t exactly surprising. Last summer, the city's Health Department announced an increase in emergency room visits due to the drug.

Chief among the K2 hotspots during that period was the area around the 125th Street Metro-North station, which groups of often-homeless New Yorkers called home (some observers called it an “encampment”).

Regulars played move and return with the cops, earned spare change by opening taxicab doors for confused tourists coming out of the station, and sometimes drank and smoked K2, sold in nearby bodegas. When high or drunk, some passed out leaned up against the station wall, sometimes removing shirts. The drug can make users warm or itchy.

Partially to address scenes like that, the City Council in October approved new penalties for sale and manufacture of the drug. In May, city officials pointed to this and enforcement of businesses that sell K2, along with education and outreach campaigns, for mitigating the drug’s effects in East Harlem and elsewhere. Multi-agency enforcement efforts led to the seizure of 10,000 packets of K2, according to a City Council spokeswoman. K2-related hospital visits dropped 85% from the summer spike.

This decrease is apparent across the city, service providers like Haken say—“the smell doesn’t hit you like a truck” at the 125th Street site, for example, and Haken says there are “significantly fewer K2 zombies” at Relief Bus locations.

But the Brooklyn mass hospitalizations make clear that the drug is still used regularly, despite being harder to get. One reason the drug isn’t widely discussed anymore is the populations who use it—often New York’s poorest.

That is true even back in East Harlem, where K2 continues to be used though advocates and city officials point to decreases.

On Tuesday, 125th Street regulars said some nearby bodegas that used to sell K2 either no longer did or had been shut down, forcing people to bring it up from Brooklyn or Bronx bodegas, for example, that had avoided enforcement. (A Brooklyn bodega near the hospitalization incident was raided by law enforcement officials on Tuesday.)

There is no law against using K2, and many in the group openly were: passing around long joints that quickly became smaller ones, huddling under the eaves of the station on the slim sidewalk, watching for opportunities to open taxi doors and make a quick buck. When one joint was finished, another appeared.

Unpredictable drug

For many, it is a drug of contradictions.

A regular who gave his name as Ousmane says the 30-minute high sometimes gave him a stomachache. He had smoked an hour or so before we spoke.

It’s cheaper than weed—one cigarette for a dollar or two, for example—but problematic for many who couldn’t reliably control it. Some pass out, Ousmane says, while some are fine. He’d recently witnessed someone smoking K2 in nearby Marcus Garvey Park. On his third pull, he started bleeding from the mouth.

It sometimes makes for issues among the regulars—fighting, hallucinating, throwing up—and brings the inevitable police attention. A common complaint among the group is the police moving them from spot to spot—away from the station to a school a few blocks away, and then back. Always shuttling, never really going anywhere. Sometimes regulars will find housing but still come back to visit.

Ousmane was clear-eyed about the drug’s unpredictability, but says it had its value.

“It makes you go to sleep,” Ousmane says—no small benefit when you’re sleeping on hard concrete, a thin layer of cardboard for a mattress. He recently got a room through an outreach provider, but he’d been living on the street for months before then, including the winter.

During those times, the drug “makes me feel good,” he says.

This is amExpress, the conversation starter for New Yorkers. Subscribe at amny.com/amexpress.