Iron Man 2

Credit for this video goes to MahaloVideoGames. You have to fight another Iron Man suit inside an electricity...bubble?He can blast you with energy, as well as pull you in so be careful. When he is close to dead another bar will come up (I was Iron Man so the second bar was War Machine, dont know if its other way around if you are War Machine) but it dont worry about that bar as after a couple more hits he will be down and the achievement will pop.