(NewsNation) — Drugs laced with the animal tranquilizer xylazine are spreading across the country, leaving people on the streets with open wounds and rotting limbs.

Kevin Dahlgren, a community health services adviser, says the proliferation of the drug, dubbed “tranq,” is “terrifying.” He’s been doing homelessness advocacy and addiction counseling for more than 20 years and hasn’t seen anything like it.

“I thought fentanyl was the worst thing I’ve ever seen in my career, but now they’ve added tranq to fentanyl, and so now it’s like a game-changer, and it’s terrifying,” Dahlgren said.

He joined “Rush Hour” on Thursday to talk about the drug and its severe effects.

You can watch his interview above.