The final boss is usually the hardest part of any video game. The entire plot of the game (if it has a plot) leads up to the destruction of the final boss. Nearly every final boss has several different forms, where he seems to be dead, but then quickly returns, often much harder than he was before. Some games have a level leading up to the final boss, while you just fight the boss immediately in others. Some well-known final bosses include Bowser (from many Mario games), Sigma (from Mega Man games), and The Shredder (from Ninja Turtles games).