Datura

Datura (also known as Jimson Weed, Devil's Apple, Thorn Apple, Stinkweed, Devil's Weed, Malpitte, and Moonflower) is a deleriant drug, similar to Benadryl, except that it grows everywhere and gives you a bad trip 99% of the time. It is usually used by retarded back-country ranchers and dirt-poor white trash who can't afford better hallucinogens, as well as faggot hippy "naturalists". 9 times out of 10 you will end up eating way too many seeds, and run naked from the cops screaming about how YOU TOTALLY SAW GOD AND IT LIKE BLEW YOUR MIND MAN! Or at least that's what people told you you did when you wake up 3 days later, naked in a Mexican prison. Also, for several days after eating the seeds, you will be rewarded with painfully dry mouth, extremely fucked-up vision, excessive sweating, nausea, and a raging headache. It's also very easy to overdose on, and plenty of people have died from it, but they're obviously pussies. Be sure to eat at least 100 seeds as fast as possible or else nothing will happen and you'll feel like a dumbass.

An artist's rendition of a Datura trip. Yours probably won't be this cool, however.

Belladonna (Deadly nightshade)

Belladonna is another anticholinergic drug related to Datura. Glory unto White Jesus! Turns out, any plant which will kill you in large doses gets you high in slightly-less-large doses. Who'd a thunk it? Belladonna, also known as deadly nightshade, contains a potent anticholinergic deliriant which is imbued with the same wonderful magicks as Datura. If you can manage to get the right dosage, rather than dying a horrible death, you will be rewarded with a horrible trip full of spiders and deadly anal penetration from your favorite childhood toys.