Tactic used when playing a first-person-shooter in which a person walks into a heavily crowded area full of enemies. This is done with total disregard for stealth and/or evasive maneuvers. In order to properly Arnold, you must also put 5 to 10 extra rounds into each enemy you face. Comes from the tactics of Arnold Schwarzenegger, who does this in every one of his movies.
Mike: Hey Alex, did you just take out 30 enemies by yourself?
Alex: Yeah, I pretty much just Arnolded.