I had this one nightmare when I was like, four.
I was in this white void of a place(think construct). I was being surrounded by these Hagar the Horrible looking cartoon vikings. I don't want to see them because I'm scared, so I close m eyes. I still see them even with my eyes closed. I yell into the distance "THIS IS NOT A DREAAAM".
I also had this one dream(not a nightmare) where me and my family were forcibly kept in this one motel by a Persian mobster who happens to own the motel. He forces us to stay there and do daily tasks to keep the room in presentable conditions or he'll "kill us". I think he said something like "you better water the petunias or I'll kill you".
Another dream/nightmare I had was when me and my family were in this fancy room(really, extremely large), and we were climbing up a huge staircase. I have a gun that can erase stuff from existence in my hand. I test it out by firing at the stairs railing. It deletes the railing. We keep on walking, but the gun starts to fire on it's own. I don't remember the rest.
Maybe I should make a thread where we post our nightmares and dreams, I have much more to share.