HI BEN
From Halopedia, the Halo wiki
Here is an easter egg on Regret with the words HI BEN on the ceiling
HOW TO FIND IT
You will need
- A sniper or beam rifle
- Sputnic Sputnic skull
Start the level Regret and proceed till you beat the drones and elites go to the outside and to your right you will see a temple with no bridge. Gernade 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.