Note: i had this dream when i was eleven years old I was at school when the aliens attacked. They caged us in one half of the school. The aliens were all green, made put of energy they stole from other human beings. They were taking the energy of the people at our school on at a time, while we were still stuck. I managed to escape from our cage (which wasn't a cage) and got to the place were the aliens were 'eating'. At the same time, another space ship landed and several other aliens came out. These aliens were the same sort as the others, but they were more skinny. They stopped the evil aliens and saved us and everything went back to normal. I am pretty sure i did something else after escaping from the cage but i don't remember what.