The are few dreams that I remember longer than a few days but this one sticks in my mind:
I was in a lift in some kind of asylum. I remember someone else in the lift with me had a jar of eyeballs. I think he may have had a leg missing as well. Not sure about that, it's kinda hazy.
But I remember quite clearly at the end of the dream being out in a enclosed courtyard in the middle of the building. SAS style men, hundreds of them, were abseiling down the walls, going into and out of the windows. I was at the end of a sunken pathway running through the courtyard and at the other end was what I can only describe as an alien from the Alien movies but dressed in the same gear as the SAS men. It also had three glowing red eyes. The eyes were on tentacles which would reach out, grab the SAS men and literally tear them apart.. The area was littered with the dismembered remains of the soldiers. I scrambled up over the edge and cowered behind some pipes as the creature sent it's tentacles out to grab me. It was clearly blind as it was trying to feel for me rather than going straight for me.
I woke up sweating and the feeling of utter terror was still with me.