Fentalyl is like morphine except it has a fast onset, so much so that people who steal used patches from patients and try to get high by using a bunch of them containing unknown dosage amounts overdose, and cant take them off since they are unconscious. Also since the dose is small and floats to the bottom of solution when u make cheap drugs, soyou can kill ppl if you aren't careful...

Fentanyl, also known as fentanil, is an opioid which is used as a pain medication and together with other medications for anesthesia.[2] It has a rapid onset and effects generally last less than an hour or two.[2] Fentanyl is available in a number of forms including by injection, as a skin patch, and to be absorbed through the tissues inside the mouth.[2]