We all have had one of those battles where everything was going right, and all of a sudden the opponent gets a lucky critical hit or you miss an attack, and then you lose.

In Pokemon Black, I was fighting some random trainer who was using one Excadrill. I was thinking, "This should be easy." He used Hone Claws ONCE, and wiped out half my party by using Horn Drill 3 times in a row, all 3 hit.