“It felt like my body was just failing on me,” a teen wrote on Erowid.org, describing the highs promised by synthetic marijuana, the random scraps of plant material sprayed with random chemicals sold in gas stations, smoke shops and on the street as a cheap, and sometimes sort-of-legal, alternative to actual cannabis. In case you think that sounds like fun—don’t.

“My organs were not working any further, it was just shutting down,” the teen wrote. “I began to shake much like someone would during a seizure.”

The serious health risk posed by synthetic cannabinoids are becoming well known, which is good, because they sound like fake news. Synthetic marijuana is believed to be the cause of the “mass casualty event” last summer in New York, when ambulances were dispatched to reports of people wandering around in a “zombielike’ state. Fake weed is causing such a stir in San Antonio, Texas—with first responders responding to eight calls of synthetic marijuana poisoning in a four-hour period on Jan. 26 and users experiencing the same mannequin challenge-winning “freezing (like a statue)” seen in New York, as well as vomiting, nausea, kidney problems and the occasional psychotic episode—that fire officials are showing tacit approval for much-safer, regular, old, outlawed marijuana.

“The main thing that we are pushing out is that this is not marijuana,” said David Miramontes, M.D., the medical director of the San Antonio Fire Department, at a widely-covered press conference on Thursday.

Marijuana, as you know, has never killed anybody, is not known to render its users comatose in an unwelcome way. That would be preferable to this stuff.

“This is dangerous.” Miramontes confirmed.

There’s also something special in the batch that’s arrived in San Antonio, a stronger, more potent flavor of the stuff, to which the city’s homeless population is taking a shine. It’s so bad that officials are worried someone will accidentally buy some—thinking it’s weed. As fire chief Charles Hood observed, innocent visitors could find themselves “in a situation where they think they’re buying a simple marijuana joint and they’re getting something synthetically altered.”

The media and police are still struggling to quantify just how bad this stuff is… and how to identify it.

As Fox News San Antonio helpfully noted, “Doctors say one of the warning signs if you are approached with this new drug is if it is already rolled up like a cigarette or a joint.” Except the kind of joint that’s the kind that melts your mind because it’s not a joint at all. How to tell the difference aside from the obvious after effects?

San Antonio authorities can’t help you there, aside from restate the obvious: Real weed is better.