Dreamt I was a schoolteacher helping on a field trip to a museum, and one of the kids went missing ... and it turned out that we were in a slasher movie and the big bad was using a GPS/RFID ID badge swiped from the student to lure us teachers off to be killed one by one. I woke up when I realized it was a slasher movie and that letting ourselves be drawn off from the group one by one was stupid.
There was aother dream after I fell back asleep, but it was much more impressionist and harder to describe what made it creepy.