Mescaline

The ether was wearing off. The acid was long gone. But the mescaline was running strong. Good mescaline comes on slow. First hour's all waiting, and then about halfway through second hour. You start cursing the creep who burned you because nothing's happening. And then...
Come on now, let's all take some mescaline!
One of the things you learn after years of dealing with drug people, is that you can turn your back on a person, but never turn your back on a drug.
Shimmering, crisping...

[Fear and Loathing in Las Vegas]