accelerating noise while the car is parked- VW GOLF

I have a 2005 VW Golf, automatic. Today after I parked the car a very loud accelerating sound came out of the engine, it sounded like I had pressed the pedal all the way down but I had not, I cannot remember if I was in park or drive but my feet was not in the accelerating pedal.

My car starts and drives fine, no more noise but I am wondering if I need to do something about this. Any idea what it might be?

Thanks 🙂