Halo: Combat Evolved Anniversary skulls
From Halopedia, the Halo wiki
List of skulls
List of Gold Skulls
Iron skull
Level: The Pillar of Autumn.
Location: This skull is located in the very beginning of the level, at the back of the Cryo deck. If facing away from the observation platform (where Sam is killed,) it is on the left side of the room, behind a stack of crates that are behind the targeting lights.
Effect: When activated, this skull will restart the level if the player is killed, or reload the last checkpoint if multiple players are killed playing co-operatively.[1]
Mythic skull
Level: Halo
Location: After defeating the first Covenant wave, walk directly towards the waterfall from the escape pod. It is behind the large boulder on the right in the water.
Effect: When activated, the health of Covenant infantry will be doubled.[2]
Foreign skull
Level: Truth and Reconciliation
Location: At the bottom floor of the Hangar, in the hallway where the Hunters ambush the Marines.
Effect: When activated, players will no longer be able to pick up Covenant weaponry.[2]
Famine skull
Level: The Silent Cartographer
Location: At the tip of the small bluff where Pelican dropship Bravo 022 is shot down and crash lands.
Effect: When activated, weapons dropped by the AI - ally or enemy - would have half the ammunition they normally would.[1]
Bandana skull
Level: The Silent Cartographer
Location: At the end of the tunnel on the ceiling in the Security console building (Warning: Grenade jump necessary.)
Effect: When activated, players will have unlimited ammo. The skull's name is a reference to the Metal Gear franchise, in which every game has an unlockable bandana that grants the player infinite ammunition.[3]
Fog skull
Level: Assault on the Control Room
Location: After crossing the first bridge and taking the elevator down to the ground floor, the skull will be on a raised platform in the center of this room and will be surrounded by fog. It will require a grenade jump to reach it
Effect: When activated, the player's motion sensor will be disabled.[1]
Malfunction skull
Level: Assault on the Control Room
Location Hint: Ladders in strange places can lead to gruesome discoveries. When you reach the gorge, you find several ladders leading to lower platforms.
Effect: When activated, one random part of the Heads-up display will disappear after every respawn.[1]
Recession skull
Level: 343 Guilty Spark
Location Hint: Only the most diligent of swamp explorers uncover these remains. Check behind the first Shade that you see in the swamp, at the beginning of the mission.
Effect: When activated, every shot the player fires would deplete two rounds instead of one. For plasma-based weapons, the depletion rate is doubled.[3]
Black Eye skull
Level: The Library
Location Hint: So many shafts, so little time. This skull is hidden at the back of one of the vents just before you enter the Index Room for the first time. Use a grenade jump to get inside.
Effect: When activated, the only way players are able to recharge their energy shields after taking damage is to melee an enemy.[2]
Eye Patch skull
Level: The Library
Location Hint: The Index hides more than just the solution to the Flood. Look behind the Index when you reach it in the very last room of the mission. Avoid the Index and carefully jump around the edge of the room.
Effect: When activated, auto-aim will be disabled.[2]
List of Silver Skulls
Boom skull
Level: Halo
Apparently even the Forerunners needed indoor plumbing. Before driving your Warthog into the underground Forerunner facility, look straight up to see a series of pipes. Walk along the cliff edge and jump to the pipe mesh.
Effect: When activated, all explosions' damage radius will increase two-fold.[3]
Piñata skull
Level: Two Betrayals
Location Hint: Don't rush, take some time to explore. After that last fight, you earned some time off. After you capture the last Banshee, fly it past the third generator room back to where you emerged from the chasm tunnel. Search the top of the underground entrance.
Effect: When activated, hostile infantry will drop a plasma grenade with each melee.[2]
Grunt Birthday skull
Level: The Maw
Location Hint: Foehammer's last stand. Use your Warthog to get up on the railing near where Foehammer goes down at the end of the mission.
Effect: When activated, Unggoy will explode in a shower of confetti with a headshot.[3]
Grunt Funeral skull
Level: Exclusive preorder promotion.[4]
Effect: When activated, every Unggoy's methane tank will explode similar to a plasma grenade when killed.