Let me start off by explaining the purpose of Halo 3 skulls, there are 3 categories of Halo 3 skulls. Gold, Silver, and Mythic. The Gold skulls are to make the campaign harder, the silver skulls are to make the campaign more fun, and the mythic skulls have no effect yet.
Skull names and effects:
Gold skulls:
1: Iron: effect is if you get killed you have to restart the level.
2: Black Eye: effect is the only way for your shields to regenerate is to melee an enemy.
3: Tough Luck: Your enemies never run away, always make good grenade throws, and always attack you.
4: Catch: Your enemies throw a-lot of grenades.
5: Fog: You lose your motion sensor.
6: Famine: Enemies drop half the ammo they usually drop.
7: Thunderstorm: All enemies are given a field promotion, and ranked up to their next available level.
8: Tilt: Makes enemy resistance much greater.
9: Mythic: All enemies have double their usual health.
Silver Skulls:
1: Blind: You lose your HUD when this skull turned on. You won’t see your weapons, shield, radar, etc.
2: Grunt Birthday Party: When you get a headshot on an enemy grunt, they will explode into confetti, and you’ll hear children cheer, “yay!” in excitement.
3: Cowbell: Explosions become much bigger in the game.
4: IWHBYD (I would have been your daddy): Unlocks hidden dialogue throughout Halo 3’s campaign.
Mythic Skulls:
1: Assembly: no effect
2: Sandbox: no effect
3: Orbital: no effect
Skull Locations:
When obtaining the skulls you have to start the level from the beginning, you can’t load checkpoints or the skull will not appear.
Gold skulls:
Iron: You can find the iron skull at the end of the very first level Sierra 117. It is behind the building Sgt. Johnson is held by the Brutes, up on the roof. You can get onto the roof at the far right side of the building. Travel to the left side of the roof to find the iron skull.
Black eye: The Black eye skull can be located at the very beginning of the second level. Their are pipes hanging from the roof, on these pipes is the black eye skull. Its on the pipe nearest to the large screen. You can gain access to the pipes a few different ways.
Tough luck: The tough luck skull is on the third level when the huge covenant cruiser flies above you. To your right is some large piping following the road you are walking on. Under this piping are support beams that go over a cliff. Jump over to the first of these beams and go to the end of it. Look to the left and the tough luck skull will be sitting on top of a rock, jump over to it and you’ve got the tough luck skull.
Catch: The catch skull can be found on the fourth level, in the first area where you have to destroy the Wraiths, when you enter the area do not eiliminate the wraiths, because the skull disappears when they’re destroyed. The skull is located on top of the circular building next to the anti air wraith, you can access the skull by grenade jumping or jumping on the back of a warthog.
Fog: The fog skull can be found on the 5th level, near the beginning of the level, as you are walking down from the anti-air gun you destroyed you encounter a ramp. You will hit a checkpoint and hear a marine yell out “there! over there!”
You only have a short period in which to obtain the skull, look up towards the right of the alley, there will be a flood jumping across the alley, you have to kill him before he jumps, because he is holding the fog skull. If you kill him too early the skull will get stuck on the roof, you have to time it just right, wait til hes directly over the alley, if you succeeded the skull will drop to the ground and you can retrieve it, if you failed don’t worry because you can just reload the checkpoint and try again. Don’t get discouraged if it takes you a few tries because its not easy to time it right, but you’ll get it eventually.
Famine Tactic 1: The famine skull can be found on the sixth level, where the path breaks into two paths, the one leading to the area where the tanks cross the bridge, and the path where you meet up with your frigate. Take the path that leads to the frigate and you’ll see a structure to your left, there will be a few ghosts near the structure.
You start by scaling the rocks to the right of the structure, and travel across it so that you pass 3 of the large support beams extending into the cliffs. Inside the fourth support beam contains the Famine skull, grenade jump to it and your done!
Famine Tactic 2: You need to hijack a brute chopper to do this tactic, when you have head back to the structure and drive it up onto the rocks next to the structure, to the right. and jump the ledge with the chopper. Position the chopper next to the fourth column and jump on the chopper and then onto the column.
Thunderstorm: The thunderstorm skull is located on the 7th level, right at the part where you get control of one of the hornets. Fly to the second force field generator, the one the Arbiter disabled and land. The skull can be found at the top of the ramp, not the entrance.
Tilt: The tilt skull is on the 8th level in the circular room where cortana starts talking to you about that she “likes to play games too…”.
Getting to the skull is somewhat hard, it requires very well timed jumps. When you enter the room head left where you see some mushrooms along the wall. Jump onto the top of these and then look up and to the right for another mushroom to jump to. Now just jump to the top of the ceiling of the room, where the tilt skull is located.
Mythic: This is the easiest skull to get, because it is located in the very beginning of the last level. Begin by heading into the canyon, but hang by the right wall. You will notice that there is a turn to the right that is off the normal trail. Head down this path, and the final golden skull will be sitting there.
Silver Skulls:
Silver skulls do not have achievements, so don’t worry if you don’t see an achievement pop up.
Blind: The blind skull is located on the first level Sierra 117, Once you kill the golden armored brutes two enemy ships will appear a little bit down the stream go towards the farthest away ship towards the cliff edge. Go to the very right and then you will see a rock jutting out over the large lake, the blind skull is found here.
Grunt Birthday Party: This is my personal favorite skull, it can be found on the second mission, right before you meet up with the the Arbiter, the piping area where drones are buzzing past you. Right before you jump down the pipe to meet up with the Arbiter, stop at the edge and look below you. There is a small ledge, jump down onto this edge and go inside the secret room, the skull is found in middle of the room.
Cowbell: The cowbell skull is found on the level The Ark, its pretty far into the level and it takes a little time to find it.
Start off by headng to the point of the level where you battle the scarab, in the middle of this dessert area your fighting it in is a somewhat large structure, grab one of the grav lifts in the structure and take down the scarab. Now head into the building that you meet up with the arbiter and go into the room with explosive crates, right after this room is a staircase/hallway that leads to a level below. The skull is located at the top of the room, position the grav lift to where you can reach the top platform where the skull is located.
IWHBYD: The skull is located on the level The Covenant. After defeating the scarabs and teaming up with the flood, fight your way to the profit of truth and kill him, then the flood will turn on you and once you have killed all of the flood head back to the entrance where you came into the building. You must jump through the rings in a specific order. The order of the rings is 1 being the entrance and 7 being the ring closest to the prophet of truth.
The order of the rings to jump through is 4 6 5 4 5 3 4
Note if you did it right the rings will start to glow and blink, the skull will appear near the prophet of truth.
Mythic Skulls:
The mythic skulls can be found on the 3 new maps that can be purchased at the Xbox live marketplace.
Assembly: To find the assembly skull, go into forge mode and load up the assembly map, the skull can be found on one of the two huge arms extending out from the center piece of the map, and you’ll find the skull.
Sandbox: You can simply download this map, in which you simply spawn next to the skull. Or you can create a path towards the skull, which is located to the right of the sunset.
Map: http://www.bungie.net/Online/Halo3UserContentDetails.aspx?h3fileid=68956613
Orbital: To get the skull simply open up forge and load the map, the skull is located down the blue corridor, towards the red door and into the next room. Face the red door you just entered and switch into monitor mode. Fly towards the top of the room facing this direction, the skull will be in the right corner of a small ledge, simply look around a bit.
I hope this helps you in finding those pesky skulls, and look out for my next guide!