I clicked on this thread thinking its a big Ley Line Worm epic monster! Sadly I was disappointed (I like epic stuff) - but at least you have inspired me to create such a creature, so in my book thats a job well done Raven.
If actual, real-world, mundane drugs could be displayed with such precise, literally fantastic detail as to exactly how much they interfere with judgment and common sense, would there be less people in the world who took them?
For some strange reason I brought with me the idea of the spell-worms of Kyuss from the fairly recent Dragon article - lord knows why, as worms are common enough anyway. I haven't had a chance to run a game using drugs as of yet, but I especially like the way you have to bite off the tail and smoke the worm to imbibe the drug.