Video of oversteering reverse spin out.
 

Crash Fail Action Compilation 2013 - 2014 Nürburgring Nordschleife Touristenfahrten Rallye VLN 24h - YouTube

How does the black car do that 2nd spin? (6:30)
The back of the car totally reverses momentum !
Where does this force come from?

I know nothing about racing theory, but here is what I've come up with.

The car is initially oversteering with the back sliding left. So the driver countersteers and cuts the wheel all the way left.
It seems the front wheel finally gets traction the moment it touches the curb (different surface?)
The driver has corrected the oversteer, and the rear tires find traction.

At that point, the car gets jerked straight (since the front wheels are still turned left), instead of continuing sideways.
This inertia shift tugs the back of the car to the right since the car is straightening.

However, at that moment, the car now finds itself on wet grass, which might as well be ice.
So the back continues to swing right like a pendulum, and ultimately the car does a 180.
If the grass wasn’t there, do you think the car would have made it through the turn without spinning around ?

tapped the brakes?

Hard to tell without being there, but I stopped vid a few times, looks like the curbing is raised. So when he hit curb, it pitched the car, LF tire grabbed, other three ended up on the slippery grass.

Slippery grass slid the back end enough so it could try to overtake the front

I'm not sure I really understand what you're asking. It's completely normal if you get sideways and you "correct" (steer into the slide) for the traction of the rear tires to eventually push the car back towards center, and if the conditions are right or you don't get your counter-steering right, the rear will then go the other way. It's called fishtailing. In this case, since he was on the edge of the road, he probably had some help from the curb and wet grass., but it can happen in any slide in any condition.

This is what happens if you go off into a slippery edge and wrestle the car back on the track. The front wheels will grab, pull to the left hard (in this case) and the rear will continue to go the direction it was going on the slippery part.

The correct way to recover from an off is to keep straight, slow down carefully to a safe pace and then slowly and carefully pull back on.

G

The number of people that let their car wander back out onto the track after spinning on the 'ring just pissed me off....

Stop the video at exactly 6:34

The car is now straight.

The car is still carrying a lot of forward momentum.

The front wheels are turned left and not straight ahead.
(Prior to that the wheels were left in relation to the car, but forward in relation to the momentum).

With the front wheels turned left while the car is moving forward, the car quickly turns left. The back end is still trying to go straight down the track.

Spin!

The first clip from the ring with the smart car that doesn't pay any attention i an @_@. I haven't gotten past that yet.

Second edit, driver at 5m 30s mark does not deserve to be in a "fail" compiliation.

Neither does the driver at 6M 23S.

Don't know, but the Volvo (I think) hitting the tree at about the 2:00 mark brought tears to my eyes. That had to have hurt.

Your confusion, is that you think the car "straightened" where the reality is its that the rotation instead changed directions.

Boy, that red and white striped caution tape on curves sure does keep the spectators safe!!