Well there were 91 votes on the wavy.com news site, but no one had left any comments. About 35% said UFO, and 35% said smoke ring from the ride.
I can't buy the explanation from the ride, because there should have been a series of the rings slowly drifting away from the Volcano ride. It
wouldn't make just one ring?!
This also looks similar to the "hole" left in the clouds over the airport terminal that was witnessed by flight crews and airport workers. (Sorry,
can't remember which airport.)