2. More simply, the second player in a two or more player video game.
I have no X Box, but I was playing Halo 3 at my friend's house a few times. He kept in sniping me and using invisibility and bullshit to kill me, but in the end I killed him like five times. I came over the next week, and after a while I got a three kill streak with the gravity hammer, and was harassing him using the hornet, hut he still won.
My other friend came over my house, and we played Star Wars Rebel Strike: Rogue Squadron 3 on my blue cube. I shot him down like four times in one game, then in rampage mode my score was three times his. About a few years later, he manages to beat me in rampage sometimes, and can beat me in a dog fight if he cheats with lock on missiles, or if I bs and fly dramatically.