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
praying mantis
fairy
I'm a fairy that lives in the forest. I like to fly around with my siblings and play games. I try to hide from humans. If they find me, I'll grant their wishes.
Keep your eyes off me, mantis. I am a beautiful fairy and not an insect to be preyed upon! Be still so I can stare at you. We fairies do not take kindly to intruders! What business have you in our church? I'm here to reflect, stare, and perfect idleness. As long as you do not harm my fellow fairies, I suppose I can permit your trespassing.  ....What is this? It's just glitter. We fairies like to look shiny and fabulous when we prance around in the air. Seems..... more... than still. Oh my, look at the time! I best be off now! ....huh. Since you're not going to be moving from that spot, why don't you look after my crystal ball here?  That sounds very.... round.