While this is technically possible you cannot do it without completely destroying your transmission. Unless you enjoy buying new cars, don't try.
Yes, you could severely damage a transmission by shifting into reverse while moving forward. But the odds of the transmission actually going into reverse are not good because there are safety mechanisms in place to prevent it from happening.
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.
Your transmission could be going bad
Bang depending on the vehicle, you will ruin the transmission.
On the vast majority of modern cars today it is impossible to actually shift to reverse while driving at high speed. Modern transmissions have an override safety device that prevents the transmission from going into reverse at any speed forward that would harm the transmission. You could put the selector in reverse, but the transmission would not shift to reverse. On older transmissions without this feature, you would probably destroy the transmission and possible have an accident.
park in reverse while going forward
Linkage needs adjustment?
Your arctic cat 580 will go in reverse and not forward because the reverse linkage is okay while the forward linkage is not.
Inspect your brake pads. I would suspect they are worn out.
Check to see that transmission linkage not making contact with wiring while gear selector in forward position.
The car might have an automatic cut off to either disengage the transmission or cut off the engine. Otherwise you will rip apart the transmission.
Of course it will you idiot. Think about it... while the car is going forward you slap it into reverse and the gears need to stop turning the other way BEFORE the can turn the other way around or it will grind all the gears and then you have just ruined your transmission