I have always just accounted this to my sleepwalking but I'm sure this kind of dream actually has a name.
For an example I will use my experience last night.

I'm laying in bed asleep then I wake up and look to the end of the bed. I see a mouse running in a zig-zag patter towards my face and it's moving rather fast. Once it gets up near my face I take my comforter and wrap it around the mouse.
I turn the light on and of course there was no mouse there.

One of the other ones that my wife loved was when I was hanging off of the bed with my hands out. I was trying to hold up the wood (I was currently building an arcade cabinet) so that it would not fall down. My wife simply walked around the bed and just helped get me back into bed and I wen right to sleep.

I'll do this quite often and I'll see things that aren't there but are really in my dream world but partially to me in the real world.

Anyone know?