Sounds like a bad trip!

I love reading Consumerist, which has a story about one man's horrible experience with a smoking cessation drug called Chantix. From the linked story:

By night four, my dreams began to take on characteristics of a David Cronenberg movie. Every time I'd drift off, I'd dream that an invisible, malevolent entity was emanating from my air conditioner, which seemed to be rattling even more than usual. I'd nap for twenty minutes or so before bolting awake with an involuntary gasp. I had the uneasy sense that I wasn't alone.

I smoked a cigarette, then tried going back to sleep. But each time I started napping, I'd dream that something increasingly ominous—carbon monoxide? Vampires?—was sucking vital essence out of me. Soon the clock on my desk read 3:20 a.m.

The most unsettling thing about sleeping on Chantix is that I never felt like I was truly asleep. Some part of me remained on guard. It was more like lucid dreaming, what I thought it might feel like to be hypnotized. And it didn't entirely go away come morning. As I showered, shaved, and scrambled into clothes, I tried to shake a weird, paranoid sense that I'd just been psychically raped by a household appliance.

That appliance sounds a little familiar (SFW).