Psycho Mantis (Metal Gear Solid)

Psycho Mantis didn't just fight Solid Snake. He messed with the player. From commenting on memory card data to forcing players to rethink how they used their controller, this was a boss encounter that made the screen feel like it wasn't the only thing under attack. That fourth-wall-breaking trickery gave Metal Gear Solid one of gaming's strangest and most memorable showdowns. He isn't as instantly recognizable as Bowser or Ganondorf, and he doesn't have Shao Kahn's physical intimidation. But ask someone who experienced that fight when it was new, and they'll tell you why it mattered. Can one unforgettable encounter beat decades of boss battles?