Green Shadows?

A couple of years ago I woke up in the middle of the night. I also saw that there were splotchy green shadows on the wall and there was no light anywhere in the room. So I woke my sister up and she told me to go back to sleep. She was scared. I switched bedbunks with her and went back to sleep. It was scarcely an hour when I fell off the top bunk to see the green things still there. No one believes me, she says I was dreaming, but I wasn't, I could tell, the way her eyes darted back and forth uneasily. Besides, I know I wasn't dreaming because I had tons of bruises from the fall. What were those shadows? Are my eyes different? Is my wall radioactive? My eyes weren't playing tricks on me, it was like light was coming from the wall and it was illuminating the covers. WHAT was it?