On the Halo 2 level "Regret", there is an easter egg with the words "HI BEN" written on the ceiling of a hidden room.
How to find it
You will need
- A sniper or beam rifle
- The Sputnik skull
Start the level Regret and proceed until you beat the Drones and Elites. Go outside and to your right you will see a temple with no bridge. Grenade jump there and go to the room to your right. Activate your flashlight and go to a left corner and snipe and you will see it.