My favorite Megaman X boss...

Yesterday on Youtube, I watched a video from WatchMojo.com about who they thought were the top 10 Megaman X bosses. While I mostly agree with their list, my favorite boss was not on the list. My favorite Megaman X boss is Agile from Megaman X2. As his name suggests, he is a fast fighter and a swordsman like Sigma was in X1 to boot. What about you? Who's your favorite Megaman X boss?