My brother had a nightmare about the Hulk in NYC I think.  Nothing specific happening, just how horrifying the size and sound of him stomping through the city would be realistically.  The Hulk seems to have had that affect on several people here in dreams.

After watching the Transformers animated movie as a child, the enormous, planet sized Unicron freaked me out.  He was the scariest animated thing I'd ever seen.  And Orson Welles's deep voice completed the terror.  So I remember a nightmare about Unicron transforming from a planet to a robot years later.  It was brief, but I heard the sound of his voice growling or something and combined with his size, it was enough to wake me up right away before the dream went anywhere.  People have criticized that it's a shame Welles's last role was in an animated children's action movie, but I thought his rich, booming voice was brilliant for this transforming planet, and fitting for the guy who went from the War of the Worlds radio broadcast to this movie about warring giant machines.  If you listen to a clip of his voice acting for it, he sounds perfect for an animated Galactus too.

Giant sized creatures always scare the hell out of me.  I couldn't watch the scenes in Fraggle Rock with the Gorgs.  They made me dizzy just looking at their size from the point of view of the small Fraggles.  Another character that freaked me out was a wrestler called Giant Gonzalez.  Even if you don't care about wrestling, look at a clip of him standing next to The Undertaker.  It's unreal that a man with Gonzalez's height and dimensions existed.  Undertaker is an over 6 foot tall, probably close to a 300 pound man, but seeing Giant Gonzalez with his proportions walking up to him was unreal.  Especially with that cave man costume.  As an adult it might look cheesy, but he looked creepy to me as a child.  Like some freakish bigfoot/man hybrid.  That scene between them looked like a cartoon come to life.

You had a Choose Your Own Adventure dream there.

The dream:

Khan standing in front of an exterior wall with floor to ceiling type windows standing proud as Kirk and the landing party (Spock and Mc Coy maybe Scotty w two random officers ) look on thru the windows as Khan positively raving about the crops the successes they have had the buildings etc as Kirk is proud as well of the accomplishments Spock is more intrigued like detective trying to solve something and has a look of concern but says nothing a raised eyebrow to Kirk 

I have no idea what happens between that and 

 at the end of the memory Khan is imprisoned and left there alone (there was somehow he had access to food in Kirk's speech to him thru the prison door explained how which I can still see but can't recall the speech or Khan's crime) then Enterprise left w the rest of the survivors.  

Now after writing thru this I can recall being confused seeing Wrath of Khan the first time as to why there other survivors besides Khan on Celti Alpha V which means this memory/dream would have been planted before Wrath was released on VHS? Or maybe the early years of HBO?