Halo Campaign Evolved 343 Guilty Spark Skulls & Terminal Locations are among the most challenging to find in the entire game. This is Mission 6, and it is the mission where the Flood first appear. The level is dark, claustrophobic, and disorienting — and two of its three Skulls are required to unlock LASO difficulty. If you are hunting every collectible or chasing the Headhunter achievement, this mission demands full attention before you finish it.
- TL;DR
- 343 Guilty Spark has 3 Skulls and 1 Terminal to collect.
- The three Skulls are: Fog, That’s Just… Wrong, and They Come Back.
- The Terminal is called Tangent II — found inside the Flood containment facility.
- Fog is grabbed right at the start of the mission — do not walk past it.
- That’s Just… Wrong requires you to kill a frightened Marine inside the facility.
- Fog and That’s Just… Wrong are both required to unlock LASO difficulty.
- They Come Back is found outdoors near the end — behind a fallen tree in the dark swamp.
- Turn on your flashlight (Up D-Pad) as soon as the mission starts — this level is very dark.
- Once grabbed, all Skulls are permanently unlocked even if you die immediately after.
This guide covers all four collectibles in the order you naturally encounter them, so you can grab everything in one clean run. Pick up the game on Xbox, PlayStation, or Steam. If you are still working through the previous mission, our Halo Skulls & Terminal Locations guide has you covered.
Before You Start: Turn On Your Flashlight
343 Guilty Spark is notoriously dark. The entire mission takes place in a foggy swamp and a dimly lit Flood containment facility. Many players miss collectibles simply because they cannot see clearly enough.
As soon as the mission begins, press Up on the D-Pad to activate your flashlight. Keep it on throughout. The Fog Skull is visible right at the start, but you can easily walk straight past it if you are not paying attention to the environment around you.
Collect in this order: Fog Skull → That’s Just… Wrong Skull → Tangent II Terminal → They Come Back Skull. That is the natural flow of the mission from start to finish.
For a broader look at every mission’s collectibles and what you need for 100% completion, see our Halo Campaign Evolved achievement and trophy list.
Skull #1: Fog — Location and Effect
Where to Find the Fog Skull
This is the first collectible in the mission and it is available from the very first seconds. Do not rush forward.
When the mission begins, walk forward through the opening area. You will pass the crashed Pelican with the radio broadcast playing. Keep going until you spot a Covenant dropship that has crashed into a large tree.
Stand in front of that crashed dropship and face it directly. Now turn left and you will see a hill rising up in that direction. Start walking up that hill. As you climb, keep your eyes on the right side. Look for two smaller trees close together.
When you see those two trees, walk between them. At the edge of the cliff just past them, the Fog Skull is sitting on the ground. Pick it up before doing anything else in the mission.
Fog Skull Effect
- Your Motion Tracker is completely disabled.
This is one of the most impactful Skulls in the game. With no motion tracker, you lose the ability to detect enemies before they are in your line of sight. Combined with the Flood appearing for the first time in this mission, running Fog on your first playthrough is genuinely rough. It is also one of the two Skulls from this mission required to unlock LASO difficulty.
Skull #2: That’s Just… Wrong — Location and Effect
Where to Find the That’s Just… Wrong Skull
This is the most unusual Skull in the game. It does not sit on the ground waiting for you — you have to take it from a Marine.
Progress through the mission into the Flood containment facility while searching for Captain Keyes. Keep pushing through the corridors, clearing rooms. Eventually you will pass through a room full of dead Covenant soldiers — the area is unnervingly quiet.
Continue through the doors, following the objective marker. Shortly after that quiet room, you will encounter a lone Marine. He has been traumatized by the Flood and will open fire on you out of fear the moment he sees you. He is not under Flood control — he is just panicking.
You need to kill the Marine. The That’s Just… Wrong Skull drops from his body. Walk up and interact with it to collect it.
This is intentionally uncomfortable. The game is making you earn this one.
That’s Just… Wrong Skull Effect
- Enemies have increased awareness of your position at all times.
- They detect you more easily, attack more aggressively, and give you less time to react.
This is the second LASO-required Skull from this mission. Combined with Fog disabling your motion tracker, running both Skulls together makes the Flood sections significantly more dangerous. For a look at how difficulty settings interact with Skull modifiers, see our Halo Campaign Evolved difficulty differences guide.
Terminal: Tangent II — Location and Lore
Where to Find the Tangent II Terminal
The Tangent II Terminal comes right after your first major encounter with the Flood inside the facility. Once the Flood make their presence fully known, you will be tasked with escaping.
Fight your way through the chaos and keep following the objectives. You will eventually enter a large room with two sets of doors — one on the left and one on the right. Both sets have distinct symbols above them to help you orient yourself.
Go through the door on the right. As soon as you step through it, immediately look to your left. You will see several dead Marines on the ground holding Shotguns — grab one if you need it, because the Flood ahead will test you.
Take a few steps toward the objective door ahead of you, but do not go through it yet. Instead, turn right and look into the dark corner of the room by the wall. The Tangent II Terminal is sitting there in the shadows. Interact with it to unlock the lore entry.
What Does the Tangent II Terminal Contain?
Tangent II is part of a multi-part lore series. Like all Terminals in the game, it contains classified intel and story details that expand on events happening outside the main campaign narrative. It is the sixth Terminal in the game overall and adds deeper context to the Forerunner story that 343 Guilty Spark hints at during this mission.
Once collected, it can be read anytime from the Collectibles section of the main menu. For more lore context across the whole campaign, our Halo Campaign Evolved review guide covers the broader narrative of the game.
Skull #3: They Come Back — Location and Effect
Where to Find the They Come Back Skull
This Skull is found outdoors near the end of the mission, after you escape the facility. It requires a short detour into the dark swamp — and it is very easy to miss if you are focused on the objective marker.
After escaping the containment facility, you will reunite with surviving Marines. The new objective is to guide those Marines to the evacuation point. As you approach the evac area, you will see a large structure with automated drones shooting lasers at the Flood around it.
Do not charge straight into that combat. Instead, when you arrive at the evac structure, hug the wall on your right and move forward along it. This lets you bypass most of the fighting. Keep going past the right side of the structure and head into the dark forest behind it.
Walk deeper into the dark swamp area, moving roughly northward (use your compass if available). Keep your eyes open for a glowing green plant next to a large tree — that green glow is your landmark. When you see it, you are in the right spot.
Behind that large tree, you will find a fallen tree branch lying on the ground like a bridge. Walk across it carefully. At the far end of the branch, look to your left. The They Come Back Skull is sitting on the ground. Interact with it to collect it.
They Come Back Skull Effect
- Flood combatants that are reanimated by Infection Forms become more dangerous than before.
This one stacks brutally with the dark, disorienting atmosphere of Flood-heavy missions. Dead bodies you thought you cleared can rise again as tougher threats. For co-op players, this Skull makes teamwork even more critical — check our Halo Campaign Evolved co-op players guide for how to coordinate these harder runs.
LASO Unlock: Why This Mission Matters
Two of the three Skulls in 343 Guilty Spark — Fog and That’s Just… Wrong — are required to unlock LASO difficulty (Legendary All Skulls On). LASO is the hardest way to play the game, and these two Skulls are mandatory prerequisites for it.
If you are working toward LASO or hunting every achievement and trophy, you cannot skip this mission’s collectibles. Missing even one of these two Skulls means LASO stays locked.
Additionally, collecting all three Skulls plus the Tangent II Terminal in this mission unlocks the Proto Gravemind trophy/achievement — a mission-specific completion reward.
Tips for Collecting Everything in 343 Guilty Spark
- Use your flashlight. Press Up on the D-Pad immediately when the mission starts. This level is dark enough to make collectibles genuinely invisible without it.
- Grab the Fog Skull before anything else. It is right at the start and takes less than 60 seconds. There is no excuse to miss it.
- Do not skip the frightened Marine. The That’s Just… Wrong Skull requires you to kill him. It feels wrong — but that is the point.
- Check both sides of the door. The Tangent II Terminal is just inside the right-side door, around a corner in the dark. Look right after you enter, before continuing.
- The green plant is your landmark for They Come Back. In the dark swamp, it is the clearest visual cue to know you are heading the right way.
- Walk the fallen tree bridge slowly. It is easy to slide off the sides. Take your time crossing it to reach the Skull on the far left end.
- Skulls are permanently yours once grabbed. Die right after collecting one and it still counts. Do not panic if you get hit mid-collect.
Frequently Asked Questions
How Many Skulls Are in 343 Guilty Spark?
There are three Skulls in 343 Guilty Spark: Fog, That’s Just… Wrong, and They Come Back. Every main mission in Halo Campaign Evolved has exactly three hidden Skulls.
How Many Terminals Are in 343 Guilty Spark?
There is one Terminal in 343 Guilty Spark, called Tangent II. It is found inside the Flood facility — in a dark corner just inside the right-side door of a large room during the escape sequence.
Do I Need These Skulls for LASO?
Yes. Fog and That’s Just… Wrong are both required to unlock LASO difficulty. They Come Back is not required for LASO but adds to the Headhunter achievement for collecting all Skulls. Do not skip either of the first two.
What Does the Fog Skull Do?
With Fog active, your Motion Tracker is completely disabled. You lose the ability to see nearby enemy movement on your HUD. In Flood-heavy missions, this makes the game significantly more tense and dangerous.
Do I Have to Kill the Marine for the That’s Just… Wrong Skull?
Yes. The frightened Marine inside the facility is the only way to get this Skull — it drops from his body after he is killed. The Marine will shoot at you on sight, so this is not just a passive pickup. You have to engage him and take him down to claim it.
What Happens If I Miss the They Come Back Skull?
If you finish the mission before finding the They Come Back Skull, you will need to replay from a checkpoint or restart the mission. The Skull is in the outdoor swamp area near the end — go there before triggering the final evac cutscene. Always check this area before wrapping up the level.
Other Halo Campaign Evolved Guides
Looking to track down collectibles across the whole game? These guides will help:
- Halo Campaign Evolved: Halo Skulls & Terminal Locations
- Halo Campaign Evolved: Truth and Reconciliation Skulls & Terminal Locations
- Halo Campaign Evolved Achievement & Trophy List
- Halo Campaign Evolved All Missions List
- Halo Campaign Evolved Third Person Guide
- Halo Campaign Evolved Machinima Mode
- Halo Campaign Evolved Beginner’s Guide
- Halo Campaign Evolved PC Requirements
343 Guilty Spark is where Halo Campaign Evolved transforms. The Flood arrive, the tone shifts completely, and two of the most important LASO Skulls are on the line. With this guide, you should be able to collect all three Skulls and the Tangent II Terminal without missing a single one — even in the dark.
