Uranus' Rings and clouds

Look carefully at the tilt of Uranus's rotation axis. It actually orbits the Sun, but, as some say, it does so by rolling on its axis.

What could have happened, hundreds of millions or billions of years ago, to shift Uranus's rotation axis this way? Many say: an impact.

Perhaps. But some traces should have remained and be still visible (it would have been an enormous scar). Perhaps the fragmented rings are a little evidence of such a catastrophe (arcs of broken rings that, perhaps, once formed a structure not as majestic as Saturn's, but at least complete)... But the truth is that nobody knows.