When you configure all the players in a videogame to use the same controller scheme, thus controlling all the characters at once with a single controller.
The practice is easily accomplished on arcade game emulators.
"Are you playing this game online?" "No, I'm controlling all four characters at once--I'm bringing the Army of Hurt."
The Shredder didn't stand a chance in single player when he figured out how to bring the Army of Hurt by controlling all four Ninja Turtles with the same game pad.
Magneto didn't stand a chance when the Army of Hurt unleashed their super moves.