No one has actually seen it, but a fairy interpreter asked a fairy and they described it as just a cloud of smoke and once in a while you trip over something in the floor.  The fairies purposely leave their trash in the floor because they think it is funny when people trip over them.
Inside the fairies church, Inside Church
bluebird
butterfly
I flutter around with my elaborately designed wings. I eat bugs and other small living items. Many people like to see me around them.
flutter flutter I am cautious around you, birds eat butterflies you know. I will stay where I am to be safe  No you are OK. I think I am going to eat that praying mantis though. Can we share? I eat bugs and other small living things too I guess. What is your name? Flutterbye, queen of the butterflies and the most beautiful of them all. I have such elaborate wings that people love to have me around them. That is why I here in the faeries church, because the faeries love my beauty. Why are you here? Oh I had no clue your majesty. I am here to discuss politics with one of the fairys. They are intelligent for their size. Intelligent but shy, that's why no one has seen them. Maybe it is only people that can't see them, maybe we can call them or try and catch them leaving their trash? Not a bad idea. We can just wait here until a fairy comes to drop their trash. Whilst we wait bluebird, tell me about you, I told you a bit about myself so I would like to hear about you Well i am a song bird. I usually am at the castle walls singing. Will you sing me a song? I can provide some magnificent light from the reflection of my wings. maybe it will lure out the faeries too! Why yes what a splendid idea! *sings*