[hogcowboy]

Is it possible you ended up on painted lines on the road? With a little rain they become extremely slick which could cause this "wheel went crazy" as you state. That condition, rain on painted surface, can put you down faster than you can blink. Just a thought. I honestly doubt the chain had anything to do with it but wouldn't rule it out completely.

 

[hogcowboy]

There were no painted lines on the road.. I send you the exact location where it happened: Rue de la Gare 4-14, 2014 Milvignes (I can't post links yet)

Those lines are not there anymore, the road is clean and the "wheel got crazy" just before those round, metallic things (I don't remember the name).

Is it possible that it skipped a teeth and got back to its place?

Looks like you have a lot of things going on that could contribute to problems. And yes, you could jump teeth and it now look fine as if nothing happened. Except for tips of sprocket teeth might show signs of jumping. But it would have to be a very loose chain to do that and as a seasoned rider it's doubtful you allowed the chain to get that far out of adjustment. I'm having trouble picturing what a wheel gone crazy is though. In my mind that's like a tank slapper where the wheel goes stop to stop repeatedly. The only other thing I can think of is if you are running on bald or nearly bald tires where they lost traction and you then chopped the throttle. That can lead to all kinds of crazy.