Is it physically possible for dreams to be influenced/controlled, even by an outside source?
Is it possible for people to control their dreams?
Yes.
Is it possible for outside stimulus to influence dreams?
Yes.
Can claims one and two be scientifically verified?
Yes, probably. There have been some experiments with exciting results.
It's funny that I'm reading this topic now. Just this morning I had a lucid dream. Admittedly, not a very powerful one. I can't blow stuff up with my mind or fly or even walk around freely--yet. (I suck at lucid dreaming, but it's okay to suck in the beginning...)
So, I found myself playing in an orchestra. That's not too weird in itself--I have actually played in an orchestra once. But, little by little things began to not add up. I don't play violin. I play clarinet. Why does this tux not fit? Why is Peewee Herman conducting, and why is he so mad at us? I shouldn't have Peewee Herman in my dream, I hardly even know who he is.
Hey, cool I'm dreaming, that is so aweso--oh, no don't go!
I began to fade out at this point, when I remembered something I read: you always have your sense of touch in dreams. So, I tried to rub my hands together and,
It worked. That's so awesome! Woohoo--aw, crap, I'm awake.
So, that's the highest level of lucidity I've reached so far. It kinda makes me want to try harder. Especially since "harder" only means doing the bare basics like keeping a dream log and trying to do impossible things--like push a thumb through a palm. (If it works, you must be dreaming.)
Anyway, this isn't a topic I can give real in depth insight into, so I'll point you to the
Lucidity Institute, and in particular the
Light and Mirror experiment.
So, can yeerks control dreams? I think I can definitely say "maybe."