Well, it took me 3 days, but I have nailed the Advanced task. I was in a hotel lobby, looking around for someone interesting to chat to, when I realised there were a lot of mirrors for a lobby. So I went up to a full length one and pulled my reflection out of it. Someone earlier said that it was odd we were using force, I didn't really use force (as I thought I would have to) because when I put my hands through the mirror, the mirror me grabbed my hands and stepped out. I asked him why I dream, and he cocked his head and said "you're me, I'm you". I yelled at him that I wanted to know why I dream, and he just cocked his head to the other side and repeated what he said before. Eventually I slapped him and asked him for a proper answer, he grinned then ran off. I ran after him, and he tried everything to make sure that I didn't catch him, like slowing down time, trying to change the scene, throwing things at me, eventually, he stopped, grinned at me again and said "see ya!" and teleported away. I tried to teleport after him, but ended up in a grey room with nothing in it.