In Gears of War 3 for the Xbox 360, you can unlock the Golden Gnasher as a weapon skin to use in the game.
To unlock the Golden Gnasher, you need to unlock the Veteran Gear achievement in Gears of War 2 by reaching Level 100 and winning a match on each of the four “Snowblind” map pack maps.
Check out my other guide for more unlockable weapon skins in Gears of War 3.