Halo: The Master Chief Collection skulls

Skulls are gameplay modifiers with the appearance of a human skull featured in Halo: The Master Chief Collection. Like in Halo 3: ODST, Halo: Reach and Halo 4, the skulls are no longer easter eggs in-game, and can also be accessed in the campaign menu without claiming them in campaign levels. A total 37 skulls are included in the collection, including several unique additions to Halo 2: Anniversary.

Skulls in The Master Chief Collection are divided into two categories: Scoring and Non-Scoring. Scoring skulls increase the challenge and reward players with higher score multipliers or bonuses to base enemy values when turned on. Non-Scoring skulls can either be neutral, such as Grunt Birthday Party, or in cases of cheat-like skulls, have a score multiplier of zero. Zero multiplier skulls like Scarab disqualify level times and scores from being recorded on the leaderboard and disable score and time-based achievements.

List of skulls
The games in which the skull is available are listed below each skull. Pre-order skulls are marked with an * and unlocked globally on December 12, 2014. With the exception of these as well as the Swarm skulls, all other skulls are unlocked from the start. Additionally, the Blind, Anger, Catch, Ghost, Sputnik, That's Just Wrong, Thunderstorm and Tough Luck skulls were not useable in Halo: Combat Evolved Anniversary at launch, but were implemented via updates in the MCC Insider Program.

Anger
"Enemies fire their weapons faster and more frequently."


 * Halo: Combat Evolved Anniversary, Halo 2: Anniversary

Assassins
"All enemies in the game are permanently cloaked."


 * Halo 2: Anniversary

Bandanna*
"Infinite Ammo."


 * Halo: Combat Evolved Anniversary, Halo 2: Anniversary

Black Eye
"Your shields only recharge when you melee enemies. Bash your way to better health!"


 * Halo: Combat Evolved Anniversary, Halo 2: Anniversary, Halo 3, Halo 4, Halo 3: ODST, Halo: Reach

Blind
"HUD and weapon do not display onscreen."


 * Halo: Combat Evolved Anniversary, Halo 2: Anniversary, Halo 3, Halo 4, Halo 3: ODST, Halo: Reach

Bonded Pair*
"Co-op skull: When one player dies, the other player gets a large damage boost that lasts a while."


 * Halo 2: Anniversary

Boom*
"Explosions have twice the damage radius. Light fuse, run away."


 * Halo: Combat Evolved Anniversary, Halo 2: Anniversary

Catch
"Enemies throw and drop more grenades."


 * Halo: Combat Evolved Anniversary, Halo 2: Anniversary, Halo 3, Halo 4, Halo 3: ODST, Halo: Reach

Cowbell
"Acceleration from explosions is increased."


 * Halo 3, Halo 4, Halo 3: ODST, Halo: Reach

Envy
"Chief trades his flashlight for Active Camo."


 * Halo 2: Anniversary

Eye Patch
"Auto aim features disabled for all weapons. You'll miss it when it's gone."


 * Halo: Combat Evolved Anniversary, Halo 2: Anniversary

Famine
"Weapons dropped by AI have half the ammo they normally would. You might want to pack an extra magazine."


 * Halo: Combat Evolved Anniversary, Halo 2: Anniversary, Halo 3, Halo 4, Halo 3: ODST, Halo: Reach

Feather*
"Player and enemy melee strikes impart more movement physics."


 * Halo 2: Anniversary

Fog
"The motion tracker is disabled. You'll miss those eyes in the back of your head."


 * Halo: Combat Evolved Anniversary, Halo 2: Anniversary, Halo 3, Halo 4, Halo: Reach

Foreign
"Covenant weapons: How do they work? Players cannot pick up or use Covenant weapons."


 * Halo: Combat Evolved Anniversary

Ghost
"AI no longer flinch from attacks."


 * Halo: Combat Evolved Anniversary, Halo 2: Anniversary

Grunt Birthday Party
"Grunt headshots lead to glorious celebrations."

Note: the plasma grenade explosion effect from the original Halo 2 is replaced with the confetti and cheering effect from later games.


 * Halo: Combat Evolved Anniversary, Halo 2: Anniversary, Halo 3, Halo 4, Halo 3: ODST, Halo: Reach

Grunt Funeral*
"Grunts die in a blaze of glory. And plasma."


 * Halo: Combat Evolved Anniversary, Halo 2: Anniversary

Iron
"Death carries a heavy price. Dying in co-op resets you at your last saved checkpoint. Dying solo restarts the level."


 * Halo: Combat Evolved Anniversary, Halo 2: Anniversary, Halo 3, Halo 4, Halo 3: ODST, Halo: Reach

IWHBYD(I Would Have Been Your Daddy)
"Rare combat dialogue becomes more common."


 * Halo 2: Anniversary, Halo 3, Halo 4, Halo 3: ODST, Halo: Reach

Jacked
"Players can only enter ground vehicles by boarding."


 * Halo 2: Anniversary

Malfunction
"Every time you respawn, a random element of your HUD is disabled."


 * Halo: Combat Evolved Anniversary, Halo 2: Anniversary

Masterblaster
"Co-op skull: One player's shields recharge to overshield level and can only melee while the second player has no shields but infinite ammo. Roles switch after a number of enemy kills."


 * Halo 2: Anniversary

Mythic
"Enemies have increased health."


 * Halo: Combat Evolved Anniversary, Halo 2: Anniversary, Halo 3, Halo 4, Halo 3: ODST, Halo: Reach

Piñata*
"Punching enemies makes them drop grenades. Beat them 'til candy comes out!"


 * Halo: Combat Evolved Anniversary, Halo 2: Anniversary

Prophet Birthday Party
"Punch that Prophet up to 11." (each punch the player lands on the Prophet of Regret on the level Regret is accompanied by an electric guitar lick).


 * Halo 2: Anniversary

Recession
"Every shot is worth twice the ammo. Save those bullets, player."


 * Halo: Combat Evolved Anniversary, Halo 2: Anniversary

Scarab
"All player-held weapons fire Scarab Gun beams."


 * Halo 2: Anniversary

SO...ANGRY...
"Enraged Brutes explode like a frag grenade if not dispatched within seconds. Base Brute score values are increased."


 * Halo 2: Anniversary

Sputnik
"Mass of objects is decreased, making them more easily displaced."


 * Halo: Combat Evolved Anniversary, Halo 2: Anniversary

Streaking
"Player shields constantly decay at a slow pace but recharge some with every enemy kill."


 * Halo 2: Anniversary

Swarm
"Hunters are much stronger. Base Hunter score values are increased."


 * Halo 2: Anniversary

That's Just... Wrong
"Increases enemy awareness of player."


 * Halo: Combat Evolved Anniversary, Halo 2: Anniversary

They Come Back
"Flood Combat Forms spawned by Infection Forms reanimating a corpse are much more dangerous. Flood Combat Form score values are increased."


 * Halo 2: Anniversary

Thunderstorm
"Upgrades the rank of most enemies."


 * Halo: Combat Evolved Anniversary, Halo 2: Anniversary, Halo 3, Halo 4, Halo 3: ODST, Halo: Reach

Tilt
"Enemy resistances and weaknesses are increased."


 * Halo 3, Halo 4, Halo 3: ODST, Halo: Reach

Tough Luck
"Enemies always go berserk, always dive out of the way, never flee."


 * Halo: Combat Evolved Anniversary, Halo 3, Halo 4, Halo 3: ODST, Halo: Reach