Like Peanut Butter and Chocolate Achievement in Halo: The Master Chief Collection

The Masterblaster Skull is a new skull modifier introduced in Halo 2: Anniversary that only works when playing cooperatively. Its effects are as follows: One player has recharging overshields but can only melee attack enemies while the other player has no shields but is granted infinite ammo; these roles will switch periodically after a set amount of kills.

With that said, grab a cooperative partner, activate this skull in the Campaign lobby and choose any of the missions within the Campaign. Cairo Station is probably the best mission to attempt this achievement given its short length. As a note, teamwork is key when working on this achievement so make sure to communicate with your Co-Op partner as you progress through the entire mission. The player who has overshields should charge into firefights and melee the enemies while the player who has infinite ammo picks off Grunts and Elites from afar with their Battle Rifle. Make sure to pay attention to when the roles swap so that the offensive player does not get ambushed in battle while their shields are deactivated. Once the mission is complete, the achievement will unlock after the concluding cutscene.