Do you have examples of cases that make you think it's more than pranks?
I have not. I am not even sure I trust all these pictures filling up the internet containing all these wonderful works of art.
If they are real, then those "pranksters" who made them must be nothing short of genius. If they are all made of folks, then there are many people lying too. There is just no way that you could make that stuff over night when it is dark. Stumbling around with a flashlight and a nail clipper. To me that sounds just as likely as an alien doing it

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So those people who say that these pieces just pop up in a matter of hours must be lying right?
I also noticed that there is a commercial aspect regarding this too. Thousands of people travel to see it, shops are set up where they sell t-shirts, stickers and whatnot. So it does stink of something, I am just not sure how to label the stink yet. I do not think I care to investigate that much either

I just brought this up to see if there were an 100% actual explanation for these "phenomenon"