I've actually had the exact opposite dream of this ONCE--I was trying to take care of these little tiny jewel-like frogs in an aquarium and I was very sad because I expected them all to die, and then I discovered that the frogs were breeding and there were more of them, and felt this terrible fragile happiness. Unfortunately, that's pretty rare, but it was nice while it lasted.
Anyway, prior to the starving guinea pig dream, I was wandering through this labryinthine house, reminded me vaguely of the Winchester House in California, and heard a little kid screaming "Help!" Now, I don't like kids* but I'm also generally not gonna pass by on the other side of the road, so I went looking. I found a balconey overlooking a courtyard, leaned over, and saw two kids, maybe seven or eight, one of whom had no face, just a blank skinned skull, and one of which had no mouth, but was managing to scream through his nose.
"Holy shit," I said. "Who did this to you?"
"It was the grey man," said the kid. "He did it."
My brain digested this for a moment then rendered the carefully considered verdict, "Okay, that's just fuckin' creepy."
"Right, then," I said. "Sit tight. I'll go kill him."
I turned back into this room (nice Moorish arches on the balcony) and went up the stairs. I knew the grey man was somewhere. I could see a sort of vague silhoutte of a man wearing one of those flat-brimmed cowboy hats and a long duster, like Wyatt Earp or something. Ironically, I remember feeling very calm about the whole thing--either killing the grey man was something well within my talents, in which case there was nothing to worry about, or he was going to chew me up and spit me out sans face, and there wasn't anything I could do about it, so why worry? It was a peculiarly cheerful mindset that I recall from one of my favorite RPG characters, Sev, who was always fun to play because she had such total self-confidence and was thus immune to regret--she always trusted that she'd done the best she could with what she had to work with, and there was thus no point to second-guessing. Even if she chose wrong, she'd done the best she could, and better to deal with it than wallow. Every now and again I have dreams where I feel like that. Unfortunately, it's hard to sustain when you're not capable of taking out a full grown troll with a single backstab, but it, too, is nice while it lasts.
I never did figure out who the grey man was, and it segued into the guinea pig thing, but it was generally an interesting if stressful night.
*A simplification of "I don't understand kids, I spend no time around them and am uncomfortable in their presence, I have no desire to have kids, and they tap into the same fear that I have of aliens, which is that they may not wish to talk and cannot be reasoned with, although they are hopefully less likely to come after me in a cornfield with a probe."