Every video game needs a strong villain. A character that the player can look at and immediately say: "That's who I'm going to be fighting 80 levels and 100 hours in the future, and it's going to be awesome."
But what about the villains that don't fit into that box? What about the antagonists who, when they first show up, appear completely unimportant? Just because at first they seem about as intimidating as a wet cloth in a hurricane, though, doesn't mean the player should ever dismiss them.
Some villains might just need time to grow, and put the finishing touches on their unbelievable powers. Others may have always been powerful and their physical nature just makes them seem weak at a glance. Others still may have just been toying with the hero - as villains are so often prone to do - just so they can make the pain of your defeat that much sweeter.
Whatever the reason, these villains are no joke, they pull no punches, and above all they do it while making you feel pathetic for losing to someone who by all rights shouldn't be this powerful.