Skulls in Halo are gameplay modifiers that were first introduced as Easter Eggs in Halo 2 to provide an extra layer of depth to the game, and to provide more of a challenge for players by altering the way the game plays. To activate a Skull, the player must first find it, which is usually a challenge in itself, as the Skulls are scattered throughout the campaign levels, usually well off the beaten track, with some requiring complex exploits, codes, platforming, glitches or even surviving a gauntlet to actually reach them.

In this list, I will be counting down the Top 10 Skulls from the perspective of modifying the game to make it more of a challenge. I have already done a list of Top 10 Most Fun Halo Skulls, and to clarify there may be some overlap between that list and this one, since not all the Skulls that make the game more difficult are necessarily frustrating or unfair (although some of them are). I will also be factoring in the difficulty required to actually retrieve the Skull, to a certain extent, but I will not be including Skulls on this list purely for that reason (so no Halo 2 IWHBYD). With that out of the way, we start with:

10 – Fog – Motion Tracker Disabled

Fog, referred to as ‘Cloud’ in Halo: Reach, disabled the handy motion tracker that has been a staple for mainline Halo games since the beginning. This effectively removes the ‘eyes in the back of your head’, as the Skull’s description states, meaning you cannot sense enemies before you can see them. This Skull is most often used by players on Flood levels to heighten the sense of fear as you are unaware of enemies sneaking up behind you, although experienced players can easily overcome this. Overall, this Skull removes a helpful feature in the game but nothing more, so it provides some challenge but doesn’t really affect gameplay all that much, unlike…

9 – Tilt – Enemy Strengths and Weaknesses to Particular Weapons Increased

Though that may sound like an overly complex description, this Skull’s very specific effects are actually surprisingly complicated, since Halo’s weapon sandbox philosophy relies on certain ‘types’ of weapons that are stronger or weaker depending on how you use them. Plasma weapons, for example, are good against shields but not against armour, and with this skull on plasma weapons become twice as effective against shields but twice as useless against un-shielded targets. What makes this Skull challenging is that it makes all enemies with plasma weapons (which is a lot since plasma weapons are the staple of the Covenant armory) twice as good at taking down your shields. This Skull does make fighting Flood somewhat easier, however, and can come in handy if you can acquire plasma weapons of your own, making it somewhat of a double-edged sword.

8 – Tough Luck – Enemy ‘Luck’ Increased

To say that this Skull increases the ‘luck’ of AI does require some explanation – technically, this Skull modifies AI behaviour so that they are much more effective at dodging grenades, vehicles, and basically any form of slow-moving threat, whilst also making it far more likely that enemies will enter an enraged state. This does create the impression that the AI is just ridiculously lucky, however, and this makes the player seem unlucky by comparison, hence the Skull’s name. Needless to say, this does create a challenge, and although this Skull’s effects also extend to your allies the sheer frustration of having enemies be able to dodge grenades that they cannot even see drains any potential fun-factor from this Skull.

7 – They Come Back – Flood are Terrifying

This Skull’s official description reads: “Flood Combat Forms spawned by Infection Forms reanimating a corpse are much more dangerous“, although they neglect to mention exactly how the Flood Combat Forms are made more dangerous – one would expect a damage boost, improved intelligence, or perhaps an expansion to the amount of weapons they can use – but no. This Skull speeds up Combat Forms so they now charge towards the player at breakneck speed, all while flailing their limbs around in an impossibly fast and suitably terrifying way. This Skull does only affect Combat Forms that had previously died and later reanimated, but in real terms, that’s still a significant proportion.

6 – Catch – Enemies Throw More Grenades

This Skull has a very simple effect, in that it makes enemies throw more grenades. Whilst this inevitably leads to a hailstorm of lethal fire pelting the player from all angles, all is not lost – this Skull also makes enemies always drop two grenades of their preferred type when killed, which even the odds slightly. An unusual quirk with this Skull is that it almost forces enemies to throw grenades with reckless abandon – they will toss explosives regardless of situation, even if it will almost certainly get them killed. This Skull would have ranked higher on the list were it not for the apparent reduction in AI intelligence and for the fact that anyone who is familiar with Halo multiplayer will knows how to deal with countless poorly-judged grenade tosses rounding every corner.

5 – Famine – All dropped Weapons have Half Ammo

This Skull is just plain cruel. Already sparse ammo for heavy weapons, sniper rifles, or basically any power weapon is now ridiculously rare, and the fact that all weapons have their ammo halved means that plasma weapons now expend their ammo within mere minutes, finding dropped ammo refills is even more essential, and every last shot has to count. For an even greater (and ludicrous) challenge, this Skull can be combined with the ‘Recession’ Skull, which makes every shot worth twice the ammo – so you are essentially left with a mere quarter of the ammo you would have in regular gameplay. To add a further level of difficulty to this Skull, it remains one of the most frustrating Skulls to retrieve in Halo 3, requiring the use of several players at once unless a rare Gravity Lift powerup can be obtained, and even then it requires precision platforming. Halo 2’s incarnation of this Skull should have made my Top 10 Creepiest Halo Easter Eggs list, since the Skull is found surrounded by twitching Flood corpses…

4 – Assassins – All Enemies are Cloaked

If cloaked enemies weren’t bad enough, this Skull amps that up to 11 by making every single enemy cloaked permanently. This includes everything from Flood to Hunters, and even includes your own Marines if you betray them. Oddly, this Skull was originally set to appear in Halo 3, but was removed, probably to make LASO (Legendary with All Skulls On) mode less infuriating. This is one of the few Skulls that could possibly be considered a whole separate difficulty in itself, as when activated even the lower difficulty settings require a whole new level of skill to master.

3 – Thunderstorm – All Enemies are at Max Possible Rank

I already covered this Skull in my Top 10 Most Fun Halo Skulls, since its ability to promote allied Elites to their highest rank does come in handy in missions where they are available. However, in any other given situation, this Skull definitely amps up the difficulty by making all enemies at their maximum possible strength, intelligence and tactical capability. Not only that, but in Halo 2 it means all Elites can withstand a direct stick with a plasma grenade on Legendary, and will draw their swords to cut through Marines with ease if they are angered. This Skull also gives all Sentinels and Elite Flood Combat Forms shields, meaning it is harder to take them out with quick successive precision shots.

2 – Mythic – All Enemies have Increased Health

The semi-unofficial ‘Mythic Difficulty’ involves playing Halo on Legendary with this Skull on, and it definitely increases the challenge by making all enemies ridiculously strong. With this Skull on, certain high-ranking Elites won’t even be vulnerable to an overcharged plasma pistol, making the age-old ‘Noob Combo’ strategy of taking out shields with an overcharge and following up with a headshot obsolete. There are a few positives to this Skull, namely that your allies are given a slight health boost too, but this seems utterly inconsequential compared to the massive boost in health and shields that even a lowly Elite Minor receives on Legendary. Combine this with the Thunderstorm Skull, and you have your own personal purgatory.

Honorable Mentions

Blind – No Heads Up Display

I include this Skull here as an ‘honorable mention’ since it doesn’t really seem fair to the other Skulls to actually include this on the list proper, because it certainly makes the game ridiculously hard. Without a Heads-Up Display you cannot see your motion tracker, health, ammo, grenades, or even the reticule – however, this Skull is rarely used in actual gameplay since it was not added with the intention of being a challenge. It is not included in the required Skulls needed to activate LASO, it does not need to be found on Legendary and it is often found near the start of the games in which it appears. This Skull was included as a means to create machinima, take screenshots or record game clips before those features became more readily available through theatre mode or Xbox capture, but if you want to attempt to actually play the game with HUD elements disabled, a better alternative is the Malfunction Skull which disables one random HUD element with each try, a much more lenient alternative.

Ghost – AI no longer flinch from attacks

One of the many Skulls to debut in Halo 2 but never return again, the effect of this Skull sounds like no more than a minor inconvenience to the player, but when activated the effect becomes immediately noticeable. This Skull essentially makes frontal assault melee attacks against Elites useless, since without the flinch mechanic the enemy can immediately melee you back, which is an instant kill on Legendary. The removal of flinching also means that enemies are no longer stunned by sniper shots, glancing explosive attacks or vehicles, which can be frustrating when pacing shots.

Jacked – Ground vehicles can only be used by hijacking

When vehicle hijacking was first introduced in Halo 2, it was hailed as a fantastic innovation to help balance vehicular combat – essentially, it meant that the player could easily acquire a new vehicle without having to waste time killing the occupant, and made dispatching heavy vehicles like Wraiths much more easy. However, with this Skull activated, vehicles can only be used if they are hijacked, which basically makes UNSC vehicles unusable. Thankfully, air vehicles are not affected, so at least it isn’t totally game-breaking.

Anger – AI fire weapons much faster

Found in the Halo 2 mission Gravemind guarded by a secret invisible Grunt armed with heavy weapons, Anger makes all enemies fire their weapons at ridiculous rates – much faster than the player can physically fire them. Plasma rifles become a stream of lethal energy, Jackal Snipers can pick off the player and three Marines in rapid succession, and Grunts fire their weapons so fast that they overheat. This Skull makes standing still a death warrant, and on Legendary allies are ripped apart by a merciless wave of weapons fire. Whilst this sounds like a nightmare, that’s nothing compared to number one on this list:

1 – Iron – ‘Death carries a Heavy Price…’

This Skull is insane. Whilst activated in Single Player, checkpoints no longer exist, meaning that if you die, you have to restart the entire level from scratch. This Skull has almost certainly been responsible for the destruction of more Xbox controllers than any other Easter Egg in the history of the console, because it makes every single level an unforgiving rage-fest on Legendary. Don’t think co-op will save you either – whilst checkpoints do still exist with Iron on in co-op mode, the death of any player reverts everyone to the last checkpoint, making teamwork and strategy essential since the cheap ‘hopscotch’ method (which involves leaving one player out of combat for the others to respawn nearby) totally redundant.

To make matters worse (or better, depending on if you like insane challenges) most of the Halo: Reach Weekly Challenges, Xbox Achievements or Maximum Scoring Records require the use of the Iron Skull, such as the Vidmaster: Annual achievement which requires four players to complete the final level of Halo 3 on Legendary in separate Ghosts, so if any player falls off the crumbling walkways, everyone is hurled back to the checkpoint. The only reason why you will ever want to activate this Skull for fun is if you want to rack up insane score multipliers, since it offers the highest point multiplier in the game for its insane level of difficulty.

And that’s my list of Top 10 Most Challenging Halo Skulls, I hope you enjoyed, and if you did then be sure to leave a like, you can also comment down below if you thought any other Skulls should have made the list. Also, you can Follow Sacred Icon or like us on Facebook for more content like this, uploaded every other day.

Click the links below for more Halo related posts!

• Halo – Ranking ALL the Halo Games
• Halo – Microsoft E3 Announcement – How Halo: Infinite could save the franchise
• Ranking the Levels – Halo 2
• Top Ten Creepiest Halo Easter Eggs