Bulltrue

From Halopedia, the Halo wiki

The Bulltrue medal, awarded for killing someone in the act of a sword lunge.

Bulltrue is a Halo 3 Multiplayer medal awarded when a player kills another player who is in the act of an Energy Sword lunge. The lunge does not have to be directed at you, you can get a Bulltrue when someone is lunging at another player. It is represented by a brown diamond with a bull on it. In the Halo 3 Beta, it was simply a red star, because the Energy Sword wasn't "supposed" to be found in the Beta's Custom Games. It is easiest achieved with dual Maulers or a Shotgun.

The name originated during playtesting of Halo 3, where a frequent response to a player shouting 'Bullshit' at his death was 'No, bulltrue'. [1]