Halo 3 Black Eye Skull
The Halo 3 Black Eye Skull is one of the many gold skulls to find in Halo 3. You can charge your shields into the Overshield range with this skull. It's on the Crow's Nest level.
Nice list of the gold skulls compiled on Wikia.
Wikia's List of Known Gold Skull
Iron
Level: Sierra 117
Directions: This skull is at end of the level. It is located behind the building where Sargent Johnson is being held captive, up on the roof. You can gain access to the roof on the far right side of the building. Travel all the way over to the left side of the roof, and the Skull is concealed in the corner.
Difficulty: Normal, Heroic, Legendary
Achievement Icon: A skull marked with a stylized drawing of a hammer
Effect: When playing co-op, if either player dies the game restarts you at your last checkpoint. On solo, it restarts the mission.
Point Multiplier: 3x
Black Eye
Level: Crow's Nest
Directions: In the same room you start in. Hanging down from the ceiling is some piping. On top of this piping, on the side nearest to the large display (the one that Hood appears on) lies the “Black Eye Skull”. You can gain access to the pipes a few different ways.
Difficulty: Normal, Heroic, Legendary
Achievement Icon: Skull marked with one eye.
Effect: Your shield does not charge normally. To charge your shields you must kill something (enemy or ally) with a melee attack (anything but the Energy Sword). You can charge your shields into the Overshield range by doing this.
Point Multiplier: 1.5x
Tough Luck
Level: Tsavo Highway
Directions: At the point in the level when the huge covenant cruiser flies overhead (after the first shield blocking the road), on your left is some large piping following the road you are walking on. Underneath this piping are some support beams that extend out over a cliff. Jump onto the first of these beams, and travel to the end of it. Look to your left, and the Tough Luck Skull will be sitting on a rock extending from a cliff edge.
Difficulty: Normal, Heroic, Legendary
Achievement Icon: A skull marked with a three-leaf clover
Effect: Enemies always make every saving throw, always berserk, always dive, never flee…
Point Multiplier: 1.5
Catch
Level: The Storm
Directions: In the first area where you need to destroy the Wraith Tanks, when you enter this area, do not eliminate the Wraith Tanks (The skull appears when the tanks appear, and disappears when the tanks are destroyed). The Skull is located on top of the circular building next to the Anti-Air Tank. You can access the roof using a grenade jump, or jumping on the back of a hog.
Difficulty: Normal, Heroic, Legendary
Achievement Icon: Skull marked with a stylized drawing of a plasma grenade.
Effect: AI will toss more grenades.
Point Multiplier: 1.5
Fog
Level: Floodgate
Directions: At the very beginning of the level, as you are walking down from the anti-air gun you destroyed in the previous mission, you encounter a ramp (next to a missile launcher). Around this ramp, you hit a checkpoint. At this point, you should also hear a marine yelling, “There! Over There!” You have a small window of opportunity at this point, but it is fairly easy to get the Fog Skull. Look up, and to the right, directly at the roof of the building next to the missile launcher. There is a single flood form (not to be mistaken with the two other flood forms jumping in front of you) which is holding the skull. Kill him before he jumps, and he will drop the skull down to the ground where you can retrieve it. Too early, and the skull will get stuck on the roof though, so just time it carefully.
Difficulty: Normal, Heroic, Legendary
Achievement Icon: A skull marked with a swirl of fog
Effect: No motion sensor
Point Multiplier: 1.5x
Famine
Level: The Ark
Directions: Near the point where the path you follow branches off into two sections (one leading to the area where you need to let the tanks across the bridge, and the other leading towards the area where you meet up with the frigate). Take the right path, as you would if you were completing the mission, and you’ll notice a structure above you / to the left of you (near the area where you encounter a few ghosts). You need to scale the rocks to the right of the structure, and then travel across it so that you pass 3 of the large support beams extending into the cliffs. Inside of the fourth support beam, lies the Famine Skull. A well placed grenade, a Brute Chopper, or deployable cover should have you up there in no time!
Difficulty: Normal, Heroic, Legendary
Achievement Icon: A skull marked with a skull
Effect: When enemies drop their weapons, they will have considerably less ammo in them.
Point Multiplier: 2x
Thunderstorm
Level: The Covenant
Directions: After you take command of one of the Hornet vehicles, fly towards the second force field generator (the one the Arbiter disabled), and land. The skull is waiting at the very top, at the end of the ramp extending over the sea.
Difficulty: Normal, Heroic, Legendary
Achievement Icon: A skull marked with a lightning bolt
Effect: Each enemy receives a rank promotion, for example, Minor Grunts will become Major Grunts.
Point Multiplier: 1.5x
Tilt
Level: Cortana
Directions: In the circular room where Cortana mentions that she “Likes to play games too…” It’s a bit difficult to get to, as it requires getting on top of the ceiling of the room. Upon entering the room, head towards the left side where you will see some mushroom shaped extrusions along the wall. Get on top of these, and then look up and towards the right for another set of extrusions. Jump to these. From here, you should be able to jump on top of the ceiling of the room, where the Tilt Skull lies in the center.
Difficulty: Normal, Heroic, Legendary
Achievement Icon:
Effect: Enemy resistances are greatly increased. For example, the Brute power armor is normally pretty resistant to human weapons to begin with and fairly fragile against plasma shots. With Tilt turned on, the Brute armor is practically 100% resistant to any human projectiles and can only be taken down by plasma bursts.
Point Multiplier: 2x
Mythic
Level: Halo
Directions: At the beginning of the level start by heading into the canyon, but hug the right wall. Very soon, you will notice that there is a turn to the right that is off the normal trail. Head a bit down this path, and the “Mythic Skull” will be sitting there.
Difficulty: Normal, Heroic, Legendary
Achievement Icon: Skull marked with a swirl
Effect: Enemies have 2x more health and shielding, and are therefore harder to kill.
Point Multiplier: 2x
