6. 343 Guilty Spark
Follow a dying signal into the swamp - and meet the Flood
Mission Flow
- Track the Marine signal through the swamp into the facility
- Descend level by level past signs of a massacre
- Survive the Flood outbreak and fight back to the surface
- Meet 343 Guilty Spark and get teleported away
At a Glance
- Enemies: Scattered Covenant survivors early; then combat forms, carrier forms, and infection forms as the Flood debuts.
- Typical length: ~45 min
- Collectibles: 3 skulls, 1 terminal
Skull Locations
FogDisables the motion tracker
Before crossing the big fallen log over the ravine, loop up the left side to the high ground overlooking the log.
That's Just... WrongEnemy awareness sharply increased
Dropped by the crazed Marine (the paranoid door guard) inside the facility - kill him to collect it.
They Come BackFlood combat forms revived by infection forms are deadlier
After returning to the surface and calling Echo-419: lead the Marines to the brightly lit central building, loop around to the point directly behind it - on a rock beside the big broken branch.
Terminal
Tangent II
After crossing the light bridge, in the interior area - loop around the wall and through the doorway. See all 13 terminals and their lore →
Legendary Tips
- Take the shotgun the moment it appears and keep it for the rest of the game (community).
- The remake's 36-round precision assault rifle shreds infection swarms.
- Don't fight endless-spawn rooms - keep moving (community).
Attempting LASO? Read the 17-skull LASO guide first.
Sources: skull locations cross-checked from DayOne, Push Square, and TheGamer guides (July 2026); terminals from Halopedia and Pure Xbox; remake changes from the official PlayStation Blog feature. Tips marked (community) come from player reports and may predate patches. Mission lengths are estimates. Last updated July 28, 2026.