I will sometimes start dreaming the moment my head hits the pillow and I’m in a halfway wake states. Often I end up dreaming, during that state, of the creepiest and crawliest insects or reptiles you can imagine eating each other.
It is often vivid enough that I can’t stay in bed and have to get out at all costs.
I had a dream like that, or I thought it was a dream, in that space of time between being awake and being asleep. I was camping in Jordan, and I looked up on the top of the tent to see a camel spider. I remember thinking: I hope that spider is on the outside of the tent, where is that cat when I need it, and I must be dreaming that spider. I rolled over and went back to sleep. Later my daughter told me that I didn't dream that spider, that she had seen it too.