In fact, ingesting just a single grain can be fatal.
It's called Gray Death because of its color, and what will likely happen if you take it.
The drug has hit the U.S. opioid scene, and the arrest of 31-year-old Jennifer Martinez, of Pennsylvania, earlier this week marks what is believed to be the first reported case in the state.
Dr. Kenneth Katz, a medical toxicologist at Lehigh Valley Hospital, said Gray Death is poised to take the country's raging opioid crisis to a new level.
"I think the mortality from this will be exceedingly high," Katz said. "My personal opinion is I'm not sure people will even get to pre-hospital care."
He said it is widely believed that a single dose of the opioid antidote commonly known by the brand name Narcan will have little to no effect.
That's because the basic ingredients for Gray Death are heroin, a synthetic opioid, fentanyl and carfentanil, which is used as a tranquilizer for elephants.
It's a combination so dangerous that you can absorb a potentially deadly dose simply by touching it for too long.
Northampton County District Attorney John Morganelli said it's just one more thing for which authorities must be concerned.
"There's a lot of pessimism in the law enforcement community because we go out and arrest folks and there's still a demand for these drugs and the supply continues," he said.
Meanwhile, Martinez is accused of selling Gray Death with three children, between the ages of 3 and 9, who were inside her home at the time.
So along with the drug charges, she's also accused of endangering the welfare of children.
But Dr. Katz says this is only the beginning, because while it may seem counter-intuitive, it will likely become more popular as more users find out about it.
"People know this, people that sell it and manufacture it know this, and they simply lead the carrot in front of the horse," Katz said.
Officials point out that the ingredient carfentanil is 10,000 times more potent than morphine.
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