That's an adorable pony rolling in an arena. It's also an adorable pony rolling in my PS of Sweden bridle.
*Head-desk*
I'd pulled off the reins for lunging and she clearly wanted to roll so after I got rid of the rest of the lunging equipment I let her go. It was only after she rolled to the other side that I realized that allowing her to roll in a bridle (especially this one) probably wasn't a good idea. I was able to get the sand off and it didn't get scratched but I certainly won't be doing that again.