[ElderScroller27]

Skull Effect:Blind You lose your HUD when this skull is turned on. You won’t see your weapons, shield, radar, etc.

Catch Skull: Effect=Your Enemies throw LOTS of grenades.

Cowbell Skull: Effect=Explosions become much bigger in the game.

Famine Skull: Effect=Enemies drop 50% of the ammo they usually drop.

Fog Skull: Effect=You lose your motion sensor

Grunt Birthday Party: Effect=When you get a headshot on an enemy Grunt, they will explode into confetti, and you’ll hear children cheer, “Yay!” in excitement.

Iron Skull: Effect=If you die, you restart from the beginning of the level.

I Would Have Been Your Daddy Skull: Effect=Unlocks hidden dialogue throughout Halo 3’s campaign.

Mythic Skull: Effect:=All enemies have double their usual health.

Thunderstorm Skull: Effect=All enemies are given a field promotion, and ranked up to their next available level.

Tilt Skull: Effect=enemy resistance much greater. For example, Brute power armor becomes nearly impossible to take out with nearly anything except for plasma bursts.

Tough Luck Skull: Effect=Your enemies never back down, always make their saving throws, and always charge you.

I compiled this list by cutting and pasting the raw data from various sites online then I edited the text for spelling and reworded some to make mroe sense, i take no credit in discovering the effect on my own. Thanks for the H3!