The quote "Do not scorn a weak club; he may become the brutal tiger" can be applied to Genghis Khan for several reasons:
1. Genghis Khan was born into a relatively weak and small tribe, but he was able to unite various tribes and clans under his leadership to form a powerful empire.
2. Genghis Khan was initially captured and enslaved by a rival tribe, but he was able to escape and later returned to defeat his captors and take revenge.
3. Genghis Khan was known for his strategic military tactics and his ruthless approach to warfare, which allowed him to conquer a vast empire and become one of the most successful conquerors in history.