Instructions
Start a new multiplayer match using the "Sandtrap" map.
Enter any warthog vehicle on the map and begin driving it towards the edges of the map. When you have traveled far enough towards the map boundaries, you will begin to be attacked by "The Guardians" which are non-player units installed at the edges of the map to prevent map-hacking. Once you have been struck multiple times, exit the match.
Enter the "Theatre Mode" and load up the most recent match replay, which should be the Sandtrap match you just exited.
Use the frame-by-frame progression tool to slowly move through the section of the replay where your warthog was being attacked by The Guardians. At some point during their attack, the warthog should have been struck by a small, yellow laser.
Switch to third-person camera mode, and follow the warthog from behind. Try to position yourself so that you are inside of the laser beam that strikes the warthog. If you have positioned yourself correctly, you should see the laser beam strike the warthog, and it should suddenly be enveloped in a bright yellow glow. You can now change to any camera angle, and the warthog will retain its strange golden hue.