Krokodil, literally "crocodile," is the street name for a crazy new drug that has spread across Russia and Eastern Europe and has recently turned up in Germany. The drug gets its name from the "scaly" appearance of addicts' skin. Because this drug literally rots people's flesh from the inside out until they die, making methamphetamine look as healthy as kale by comparison.
Why would anyone take such a drug? Well, krokodil is essentially desomorphine, a morphine derivative that is roughly 8 times as powerful as heroin. This means it is also approximately 8 times as addictive as heroin. So you can see the problem.
Why is krokodil primarily produced in Russia? Well, it turns out that desomorphine can be synthesized extremely easily and cheaply in a kitchen sink from ordinary codeine, and it also turns out that in Russia, codeine is available over the counter to just about anybody.
The problem is that the cheap way to synthesize desomorphine from codeine involves mixing codeine with benzine, paint thinner, hydrochloric acid, and red phosphorus. All four of these things are extremely toxic to human beings, and injecting them directly into your bloodstream is a recipe for a quick, painful, and messy death.
It is estimated that most krokodil addicts die within 1-3 years of first use. Judging from the veritable genre of Youtube videos of krokodil users (WARNING: some things on the internets, once seen, can never be unseen!), I would say that those who die in only 1 year are the lucky ones.