It can be pretty difficult to create a memorable boss battle, they are after all an industry standard and they're the kind of game element that immediately attracts extreme praise or criticism. The market is a difficult one: each game can include multiple boss battles, and multiple games can be released in a week, so the question is how the developers make theirs stand out. Even though this fight took place more than ten years ago, it still remains one of the greatest (and most unique) boss battles of all time, chiefly because the techniques used by Psycho Mantis in order to mess with the player are brilliant. First it starts off with Mantis commenting on the things the player had done up until that point in the game, which was pretty cool, but Mantis steps up his game when he actually looks at the players memory card and makes comments regarding other games. This is the moment that left most gamers looking on in disbelief and turned Mantis into an instant classic villain. Mantis also moves your controller using the power of his mind (actually the vibrate function) and the best part is that all of these actions dont actually feel out of place despite breaking the fourth wall. Mantis is psychic, after all, so these powers make sense. In the end, the player experiences an interaction with a virtual villain that is unmatched even to this day. https://www.youtube.com/watch?v=f2Hkb1UHmSM
Radu recently left a boring job and now writes stuff on the internet. When he's not here he's probably writing for GeeKiez. He's into wrestling, video games and a ton of TV shows, as well as all things weird or science-y. Feel free to talk to him about this stuff on Twitter.