GOOOAAAAALLLL! is an achievement in Halo: The Master Chief Collection. It is unlocked by shooting the Soccer Ball located on the level Metropolis. The achievement is worth 10 gamerpoints and can be unlocked on any difficulty.
The easiest way to access the soccer ball is to fly to it using a Banshee. As such, players should plan to unlock this achievement immediately after finding the Scarab Gun and unlocking the Scarab Lord achievement, utilizing the Banshee acquired for the latter achievement to unlock the former.