I did this once. I don't know if I was controlling it or not though, but in the dream I did look at myself in the mirror. The setting was creepy, I was in an older 2-story house and it was all dark. The place looked abandoned and slightly run down (like in those horror movies). I remember walking to the bathroom in my dream and looking in the mirror. I saw myself. I looked away and looked back into the mirror and I noticed my front teeth were missing! I was creeped out! Then as I stared at myself the gap in my teeth began to come together (with my two teeth still missing). I began to get even more freaked out, and I tried to change my expression in the mirror. But no matter what I did my reflection never changed. I'd turn my head, try to do a bunch of random expressions to see the reflection change but it wouldn't. It just stayed there looking straight at me, as if there was someone else on the other side that looked just like me. I got so freaked out, I woke up right after and immediately walked to a mirror to look at myself to make sure I wasn't still dreaming.
I know this is a really random dream(aren't all dreams random), but this is one of the strangest/weirdest/creepiest dreams I've had. The whole mood/setting of the dream was just eerie. I know that dreams can be interpreted in a bunch of ways, so I gave up/don't want to look for a hidden meaning in it. This happened in late 2011.