One of the most iconic and brilliantly clever boss fights of all time, the Psycho Mantis fight from Metal Gear Solid has Mantis break the fourth wall by appearing to read Snake's mind. Not only would Mantis make the Dual Shock controller vibrate, but he'd pretend to change your TV's channel (the screen would go black) and even read your memory card to talk about other Konami games you'd saved on it. During the battle, Mantis continues to read Snake's mind, blocking his attacks, and so the only way to prevent this is to switch game controllers, a ridiculous but totally inventive gameplay mechanic that asserted Hideo Kojima's stature as a visionary, virtuoso game creator. The fight from then on was a piece of cake, but nobody who has ever played it is able to forget this superbly inventive duel of wits.