Fentanyl became HUGE because when the USA gave control over Afghanistan back to the Taliban a condition was to stop all poppy (heroine) production. 80% of the worlds heroine came from Afghanistan. When that stopped, fentanyl was suddenly everywhere and heroine users started using that instead. I have a European friend who was addicted to heroine and he said that almost overnight the prices had doubled. I think it comes to no surprise that with the little money he had, he bought fentanyl instead. He was also very lucky that he had a huge tolerance for substances and didn’t die when he took a wrong dose the first time.