Eh, that will buff right out...
haha. That thing had some SERIOUS wing folding going on. It looked like one of the wings let go and that is why it went down. The Bixler 2 is supposed to have a much stronger wing spar than the first one. If you do get another easy star, I would definitely get an extra spar to put on that wing. 4mm or a bit bigger.
And you have to love the kids lol. My kids do the same thing.