The Fog skull isn’t the most annoying skull to use throughout the campaign of Halo Infinite. This skull disables the motion tracker on your radar. Of course, this makes it harder to find enemies. This skull is hidden better than most of the other skulls in the game. Here is where you can find the Fog skull in Halo Infinite.
You can find this skull immediately after completing the Outpost Tremonious quest since it is in the first location of the open world. Use the map above for reference. The Fog skull is located to the west of FOB Alpha. To make things easier, you can capture FOB Alpha, so you have a respawn point in case you fall.
From FOB Alpha, head west into the mountains. Stick to the edge where you can see the hexagonal pillars. Follow them until you find a cave on the edge of the map. This cave is near some Banished objects, and you might fight an enemy or two along the way. Stop going when you find a doll near the entrance to the cave-like area.
When you find the doll or reach the cave entrance, look to the left. As shown in the image above, there are a few hexagonal pillars that you can climb up. Use your Grappleshot to climb up the pillars. We recommend having the 40% faster cooldown upgrade to help make the climb.
Follow the path by climbing up the pillars until you reach the area with a slightly raised floor covered in UNSC soldier helmets. You will find the skull resting among them. You can also use a Banshee to fly in through the side of the cave if you prefer that instead.