Brohammer is an achievement in Halo: Combat Evolved Anniversary and Halo: The Master Chief Collection (in which it is called Bro Hammer). It is awarded for completing any level cooperatively on Legendary difficulty. It is worth 50 gamerpoints in Halo: CE Anniversary and 10 in the Master Chief Collection. Receiving this achievement also unlocks the "Standard Operating Brocedure" and "Brovershield" achievements if the player hasn't completed a level cooperatively on Normal or Heroic, respectively.
In the original Halo: CE Anniversary it is represented by two Sangheili skulls over the Heroic difficulty shield. In The Master Chief Collection it is represented by a screenshot of an asteroid belt on the map Nebula.
The achievement is a reference to Carol Rawley's callsign, "Foehammer".