Grand Theft Halo
From Halopedia, the Halo wiki
Grand Theft Halo
Grand Theft Halo is an achievement in Halo: The Master Chief Collection. It is unlocked when a player boards five enemy-occupied vehicles during one match in Halo 2: Anniversary multiplayer. The achievement is worth 10 Gamerscore and can be unlocked in both matchmaking and custom games.
Trivia
The achievement is a reference to the video game series Grand Theft Auto.