As I was trying to make a turn into the parking lot of a convenient store, my Tesla Model X started accelerating suddenly and unintendedly without my foot being on the accelerator. I kept pressing on the brake to stop the car, but it would not stop. I had no control and while it accelerated for 15-20 yards eventually it hit two other cars that were parked there. This happened so quickly. We all were terrified and shocked as I could not stop it from accelerating. I kept yelling "it is not stopping" to the person seating on the passenger side. I am confident that I did NOT press the accelerator pedal. The car was not on autopilot. My initial speed was probably 5 miles/hour, but it accelerated so suddenly that four airbags deployed, and the car is not drivable. Insurance company is evaluating whether the car is repairable, but I am afraid of driving with this car again until the problem is found and fixed. This could have turned to a major tragedy.