Skidding control when parked

Can you tell me if I am imagining things with my brand new undamaged car - I parked it on a snowy slope a couple of days ago, then a few minutes saw it sliding backwards down the hill towards a gatepost. Panic.
Then I am sure I saw the back wheels driving the car to slow down the skid and it stopped short of the gate. Could it have sensed itself sliding and switched itself on even though the key was in my pocket yards away? Or am I just bonkers?

Bonkers!

Wonder if the rear integral steering is what u saw

You must have got the K.I.T.T option???

Hi, what is the K I T T option ? some joke or something serious?

Allways put your emergency brake on; it should not slide on a slope.