I had this experience a couple months ago:
I was over at my best friend's house (we'll call her Lily), our friend "Bob", and Lilly's friend from out of town (we'll call him Tom).
The four of us were sitting around the kitchen table (we may or may not have been smoking a certain herb), having a grand old time. I think it was around 11pm.
Tom starts feeling kinda sick, so he gets up to go into the living room and lay down on the couch; but as he's walking he just falls, completely passes out. He wakes up in a few seconds, still not feeling too great, and says that while he was out he had a kind of "dream" about his brother (I don't remember the details). With the help of Lily and Bob, he finally makes it to the couch. Lily stays in the living room with him, while Bob and I go back into the kitchen.
Well, at this point I'm starting to not feel so good. I feel a little dizzy, so I lay my head down on the table. And then, I was gone. I passed out, too. Here's the weird part: I dreamed while I was out. This may not seem strange to you, but I have passed out a few times before this and this was the first time I ever dreamed. It wasn't a good dream, either. All I remember from it was darkness and screaming.
Now, it gets weirder...
A couple weeks ago Lily and I were at "George"'s house (where occasionally a very dark energy hangs out), and the next night we were over at Lily's house again. It was kind of late at night, again. And we were sitting at the kitchen table, again. However, this time it was only Lily and I.
I start to get that dizzy feeling again, so I lay my head down on the table and ask Lily for a glass of water. She gets up to get it for me, but while she's at the sink, I...go away...
I'll tell it to you the way she described it to me:
"You did this limp thing, and then you lifted your head up and looked at me with these huge dead eyes."
Apparently, I then proceeded to arch back over the chair. Then, I launched myself at her, hissing and growling, and (she said) really trying to hurt her. She had to physically restrain me.
After a couple minutes of this, my whole body went limp and I came back.
It took me a few minutes after I "woke up" to figure out that I wasn't dreaming. I felt very shaky, and was covered in cold sweat, but I didn't remember anything that happened and still don't. And there wasn't a dream this time, just a large blank spot.