I think mine might have been chunks of some kind of spongy filter in there covered in mold. It spit out tons of those chunks, and my boyfriend tried to clean it out and found nothing but black stuff. It did leak inside a small amount. Every now and then when it rained a lot I could see a drop of water coming down from it. I slept right under that air conditioner for a few months until I finally noticed the black chunks in my bed!