Cold Fusion
From Halopedia, the Halo wiki
Cold Fusion
Cold Fusion is an achievement in Halo: The Master Chief Collection. It is unlocked by killing an enemy player by detonating a fusion coil in Halo 2: Anniversary multiplayer. The achievement is worth 5 Gamerscore and can be unlocked in both matchmaking and custom games. It also unlocks the "Fusion Coil" Multiplayer Emblem.