It goes into reverse gear, nothing else.
Nothing... But it probably wont let you start it until you put it back in park.
In brief, you will blow the engine.
The engine blows. Usually pistons shoot into the engine. In most cases the engine will have to be replaced.
No, as long as you come to a complete stop before you put it in park.
car will jerk forward and then go in reverse
The car will not be ready for use so you have to warm up the engine or just ride it often
Car no move
I assume you mean add fuel by pressing the accelerator. In which case the engine runs faster.
Your car has an automatic transmission which includes a "neutral safety switch" to prevent the car being started while the shifter is in any position except "neutral" or "park". This switch is activated by the shift lever and prevents voltage to the starter solenoid when the car is in gear (drive or reverse). This is a safety features that prevents the car from lurching ahead or backward while starting.
Nothing if you are sitting still. However if you are moving forward and it is an older car, you may be replacing a transmission. Most if not all cars today with and automatic trasnmission have a failsafe to prevent going into reverse while going forward.
Almost always. Unless the airplane happens to be an ultralight, or the car happens to be a Hummer.
The clutch will normally be pushed out and/or the transmission will disengage on its own. Many vehicles also have electronic systems which shut off the engine and allow the vehicle to freewheel.