the answer is kick so don't stand behind a horse and make it scared
A horse's first instinct if it is afraid is to run.
A horse's first instinct when frightened or startled is to run away. The second instinct is to fight in order to protect itself.
When a horse is frightened or afraid their first instinct is to Flee, run or get away. known as spooking.
flight or fight and if it is afraid it is going to have a flight instinct
to bite
It will bolt.!
Bolt.
horses first instinct is to run, to get away from whatever is scaring them and if all else fails, defend itself. -HorseOwner
its first instinct is usually to flee from that person but depends how scared it is if its not that scared it will just bite
To Fight Or Kick.
Instinct
A horses first instinct when fearful is almost always to flee first and ask questions later. In some cases though the horse is attack, but that is not common.