Opioid addicts like "Aaron" know any hit of a street drug could be your last.
"It's always in the back of your mind but option addiction is one of the strongest so it doesn't matter," he says.
So this newcomer to the streets of Houston has authorities really nervous.
It's called carafentenil.
It's between ten and 100,000 times more powerful than morphine, and it's been turning up on our streets and making its way into the crime lab.
"It's really terrifying because it's so potent. You can't even see what could be a lethal dose." says Dr. Peter Stout with the Houston Crime Lab. He says it's used to knock out elephants and hippos.
It's getting here through the mail from China. Drug dealers are using it to cut heroin and meth or even make real looking pharmaceuticals. It's cheap, powerful, and there's no field test for it.
It's easily absorbed through the skin, so Chief Art Acevedo says officers will be taking more precautions when dealing with any drugs in the field.
"We're in the process of ordering better, thicker gloves for our personnel and we're asking them to double-up and put on two layers of gloves for extra safety." he said.
"That just increases the desire for it. Yeah."