Many drugs in my opinion.
LSD, not just can easily kill you because of heart attack but it can also drive you crazy without salvation, i can admit that i tried it and i almost died, worst nightmare i ever had in my life.
Heroin, really large number of heroin overdose deaths that is known everywhere, even if you don't die it ruins your life in bad way.
Crocodil or Shisha, it's a Russian made drug x10 times stronger than heroin, and guess what it's made from,.. battery fluids.. yes fuckin battery fluids, if you injest it on vens through skin it can burn your skin and inner body organs from inside, the skin death appearance looks like it's coal or crocodil skin, that's where the name comes from, and it can really break your body in pieces without you noticing it.
Scopolamine or "Devil's Breath", in my opinion is the most dangerous, well known as "rape drug" it erases your consciousness and makes you vulnerable to any order anyone makes you ie. if someone tells you to go withdraw your bank account and come back to give him/her the money you will do it without asking, a small mg over dose can kill the person given to, people used to kill just by blowing the dust drug on the victim's face, or whores makes you sniff it from their body without you noticing that you are getting drugged, tho imagine someone nocks the door to you and once you open it he blows this dust in your face :wat: insta scopolamine overdose death.