Only available in Russia, it's a heroin substitute, and it essentially eats your flesh.

http://www.independent.co.uk/news/world/europe/krokodil-the-drug-that-eats-junkies-2300787.html

'It was given its reptilian name because its poisonous ingredients quickly turn the skin scaly. Photographs of late-stage krokodil addicts are disturbing in the extreme. Flesh goes grey and peels away to leave bones exposed. People literally rot to death.'

These pictures/video of the sufferers are NOT FOR THE FAINT HEARTED

http://www.pocketfives.com/f13/new-drug-krokodil-russia-unreal-nsfw-nsfw-nsfw-nsfw-not-good-nsfw-641095/