The Return of Megg
From Halopedia, the Halo wiki
The Return of Megg is an achievement in Halo: The Master Chief Collection. It is unlocked by listening to the Megg Easter egg on Cairo Station. In order to activate the egg, the player must play on Legendary difficulty with the Thunderstorm skull active, and must reach the final room of the level without taking any damage. The achievement is worth 20 Gamerscore.
Tips
It is highly recommended that the player activate both the Scarab skull, which will turn all of the player's weapons into Scarab Guns, and the Envy skull, which will replace the player's flashlight with the Arbiter's active camouflage armor ability. These skulls will make the level dramatically easier, though the player will need to be careful of their own splash damage.
Players may also wish to turn on the Black Eye skull, as it will prevent the player's shield from recharging automatically, thus preventing shields from recharging before the player notices they have taken damage.
If a player does take damage, they can reload their checkpoint and try again. If however the player activates another checkpoint after having taken damage, they will have no choice but to start the level over.
