A point in time when a person, place, or thing's potential is at its most, and that potential is acted out in a way that causes astonishment, disbelief, or an unpredictable event. It is when the act is completed that they are considered "hoss"
PERSON: Did you see what that guy did? What a hoss!
PLACE: Cancun is a hoss place to go to for spring break.
THING: Katrina was a hoss storm that caused unimaginable carnage.