Seek and Destroy
From Halopedia, the Halo wiki
Seek and Destroy is a Bungie.net campaign medal available in Halo: Reach. It is earned by killing certain special Elites, usually gold Sangheili Ranger. It is represented by a golden Ranger helmet spouting purple blood on top of a four-pointed star. The medal does not appear in-game and can only be viewed on Bungie.net.
On March 31, 2012 Bungie.net ceased updating Halo game stats and player records, transferring all record-keeping responsibilities to Halo Waypoint. As Seek and Destroy could only be viewed on the site, it is effectively no longer awarded.