Boss Guide: Eye of Cthulhu – Terraria

Boss Guide: Eye of Cthulhu – Terraria 1 -
Boss Guide: Eye of Cthulhu – Terraria 1 -

This is a guide on the early-game boss of Terraria named the “Eye of Cthulhu”. It could easily catch a newer player off guard, and likely kill them, but that is why I am making this. To help with questions related to health, or loot, or the best gear to use which can be easily obtained without large-scale progress, this guide will explain all the information I can retrieve from my own game without outside sources. However, I am testing and studying using a Journey-Mode character and world to save time with difficulty differences, among other things, and there may be some qualities that differ between, for example, Master Mode worlds and Journey Mode worlds set to Master difficulty, and my apologies in advance for any inaccuracies.


The Eye of Cthulhu is a very early-game boss in Terraria. It can spawn naturally quite suddenly, as I will explain further on. While it is definitely not the worst foe you will encounter, it can have the advantage of shock if you don’t know the warning signs and conditions. This guide will cover, as said in the description, health of the boss on varying difficulties, loot on said difficulties, and some ideas on weapons, armor, accessories, and an arena.
As this is quite complicated information to find-Defense so much I could not even do so at this time-there may be mistakes. I understand if mistakes cause anger, and if there is any, don’t rage. Politely notify me in the comments. I will also appreciate added information for myself and whoever should read your comment. This applies not only to this point in the guide, but before and after it.
Now, on to the journey… through this guide and through your game.

Summoning The Eye of Cthulhu

The first thing you should know, is how it spawns. After all, you can’t fight it and apply the information here if it doesn’t spawn, right?
There are two ways it may be summoned, one natural and one with an item (later in this section on that).
The natural way is this: If at least three N.P.C. characters are present in your world, then there is a very high chance that a green message with these words will appear in chat at dusk:
“You feel an evil presence watching you…”
If that appears, be ready for a battle: Once true night begins, the Eye of Cthulhu will spawn. However, know that the number of N.P.C. characters on your world WILL include:
*The usual N.P.C. characters that move in, such as the Guide or Nurse.
*If you should have somehow obtained the Zoologist at this point in the game or brought her wares from another world, town pets summoned with the Cat License, Dog License, or other item WILL count as N.P.C. characters.
*Though this one makes very little sense, the Traveling Merchant will also count towards spawning the Eye of Cthulhu.
I do not at this time know if any other requirements are present, however I will update should I discover them.

The second one, the item, is simple: Obtain the Suspicious Looking Eye, and use it during night in any location. The item can be obtained in chests underground, usually gold or part of a building, or crafted using six lenses at a Demon Altar (in Corruption worlds) or Crimson Altar (in Crimson worlds). The altars can be found frequently in their respective “chasms”. Lenses are common loot from all forms of Demon Eyes, flying eye-like enemies that appear during night.

The Basic Attacks

When the Eye of Cthulhu spawns, it will essentially appear as a much larger version of a Demon Eye. It, however, follows a far different pattern:
* When it first spawns, it will rush in from either the left or right side of your screen, said side is completely random. It will slow down and drift upwards when it first comes close to the player. Trust me, when you fight later bosses (looking at you, Queen Bee) you’ll wish they did this…
*Afterwards, it will likely begin to spawn Servants of Cthulhu, which look like tiny versions of Demon Eyes. While it would make sense if it spawned more on higher difficulties, I have not noticed it doing so.
*Occasionally, it will slowly charge the player.
Once it has been lowered to a certain amount of health, it will change to its second and far more dangerous form. I have noticed on Expert and Master difficulties, it will reach this form slightly faster-while Cla*sic appears for it to change at slightly below half health, Expert and Master appear to transform it when it has reached somewhere above half, though still not absurdly high.
When the Eye of Cthulhu switches form, it will shed its iris and pupil to reveal a menacing maw beneath, full of long fangs. Not only that, it will also considerably change its pattern:
* It will now spawn Servants of Cthulhu much less, if at all. However, during the original transformation, it will spray the Servants of Cthulhu in a ring as it spins.
* It will, however, use its charge attack almost constantly, and said charge attack is much faster.
* In Expert and Master difficulties, be even more cautious of this form, as it will begin to use a very dangerous attack, using it more often the lower the health: It will charge at you with overwhelming speed two to five times in a row. This is best avoided with several things-I’ll get to it in a couple sections.
As you would expect, when it reaches zero health it will die, and loot will appear depending on the difficulty it was spawned in. This will also be covered, of course.

Health, Defense, and Damage Stats.

The base health of the boss is 2800. On Expert difficulty, this rises to 3640, and on Master difficulty, it becomes 4641. Even the latter is a optimal health pool for a boss at such a early point.
The base damage of the boss, according to the Bestiary, is 15. After an intentional death to quickly end the Master battle that let me see the damage, I have now discovered the damage for Expert is somewhere near 32. The damage on Master appears to be 41, a very bad day if you are under-prepared. These damages, of course, apply to contact damage in the first form, and the second form may increase relative to each number.
As for Defense, I deeply apologize, but I cannot find a believable method for finding it. However, I am able to provide the Cla*sic defense, as it lists in the Bestiary as 12. Again, my greatest apologies, I tried with the math that would seem to find it, but I cannot think of another way. But do not fret, if I somehow figure it out and the number makes sense relative to previous difficulties, I will update.
As for knockback, it is completely immune to knockback of all forms.
Now, moving on! Time for the loot.

The Loot

So, the loot will drop once the Eye of Cthulhu is killed. The loot is slightly complicated, but I shall explain.
The first thing you’ll notice when it dies the first time ever is a special kind of loot-the achievement:
“Eye on You”
“‘Defeat the Eye of Cthulhu, an ocular menace who only appears at night.'”
It speaks for itself, as you can tell. It is immediately awarded upon the Eye of Cthulhu’s death if you were involved in the battle. Now, let me explain the item loot.
On all difficulties, it will have these possible drops on Corruption worlds:
*A good amount of Demonite Ore, mostly useful outside of profit when combined with Shadow Scales from the Eater of Worlds boss.
*Unholy Arrows, which are pretty good against future encounters if you have yet to obtain other piercing weapons (up next)
*Corrupt Seeds, which can be planted if you wish for corrupted gra*s I suppose.
Also on all difficulties, these drops are exclusive to Crimson worlds:
*Crimtane Ore, whose bars can be sold or used with Tissue Samples from the Brain of Cthulhu boss to obtain some equipment.
*Crimson Seeds, I recall, can drop, and are about as useful as their Corruption counterpart.
*However, no arrows drop here.
Now, here’s the complicated part: On Cla*sic difficulty, these may drop directly from the boss along with the previously mentioned loot of your evil:
*Eye of Cthulhu Trophy, one of its fangs mounted on what appears to be a Weapon Rack and used for decoration.
*Eye of Cthulhu Mask, which is pretty much what it says on the tin: a cosmetic armor piece best used in the social helmet slot (the slot to your left of the armor slots) to put on a mask depicting the Eye of Cthulhu’s second form.
*Health Potions and a large amount of Hearts, likely for healing if you had a rough fight.
On Expert difficulty, an Eye of Cthulhu Treasure Bag will drop instead, but don’t panic. All previously mentioned drops can be inside (excluding the items of the opposite evil from your world’s, of course), along with the following:
*Shield of Cthulhu, a very good early-game shield that makes future battles against this boss much simpler (again, up next).
*Several cosmetic armor pieces I believe.
There is something interesting about the bag: it gives Corrupt or Crimson drops depending on the world you currently are in, not the world it was acquired in. For example, if you were to kill an Eye of Cthulhu in a Corruption world, then leave to a Crimson world before opening the resultant bag, that bag, should you open it within the Crimson world, will actually contain drops from Crimson worlds, despite being obtained in a Corruption world. If you have both types of worlds, you could use this feature for profit, as, when selling to shopkeepers, Crimtane Bars sell for slightly more than Demonite Bars, at 36 silver 11 copper for one bar, compared to Demonite Bar’s 27 silver 77 copper, for the Goblin Tinkerer. However, the best vendor for selling evil bars at this point in the game is the Mechanic, who buys Crimtane Bars for 42 silver 39 copper a bar. If you cannot defeat Skeletron, as the Mechanic is in the Dungeon and therefore requires a Skeletron kill before rescuing her, don’t fret-the Stylist comes at an extremely close second at 41 silver 93 copper for one Crimtane Bar, and requires nothing more than finding a Spider Cave and rescuing her, with no required bosses to be slain beforehand. Don’t worry, no matter the vendor’s personal price for the bar, Crimtane is ALWAYS the more expensive one. Not sure why, it makes no sense, but that’s how it works apparently.
On Master, the same Treasure Bag with the same contents will drop, but two pieces of loot are exclusive to this difficulty, and drop directly from the boss when they appear:
*The Suspicious Grinning Eye, which will summon the Suspicious Eye pet when used or equipped. Purely cosmetic, yet cute.
*The Eye of Cthulhu Relic, a gleaming golden statue of the boss’s second form floating on a base, used for decoration. I mean, it gives a tiny amount of light, but there are far cheaper items that glow far brighter.
That was a lot, but we can’t stay here forever. Like I have now mentioned several times in the guide, the tips and recommendations are here.

Tips, Recommendations, and an Arena

Links to images I have of an arena that may help:
This one shows the bottom, I could not fit it in one image:
Boss Guide: Eye of Cthulhu - Terraria - Tips, Recommendations, and an Arena - 9D7D16FF2
This one shows the top:
Boss Guide: Eye of Cthulhu - Terraria - Tips, Recommendations, and an Arena - 7BCAC15C4
So,I know it is hard to see, but I did my best without spending a long time figuring it out. I will improve if I happen to find out how to do the traditional “inserted images without links” thing. I apologize if its size causes problems.
Basically, the concept is a large box with doors at the bottom to allow ease of access and exit, with several platforms every few blocks spreading the entire length of the box. Some holes are in the platforms to allow better mobility. With such a large space, it is crucial that campfires are the source of light, at least in a boss fight- in other cases, anything but torches is fine. The only time torches should be permitted is:
A. You have already defeated the Torch God “boss” and used the Torch God’s Favor.
B. You very carefully put down just enough torches that you’ll need-in such a open space yet completely in the area that the Torch God counts as close enough to trigger.
The reason? Well, short yet freaked-me-out-story: I saw a Stylist in a nearby Spider Cave and rescued her. I had no clue the discovery I was about to make: I completely spammed Bone Torches everywhere on the walls when my vision decreased, however I first noticed the beams of pink light shooting me. Turns out, I had accidentally triggered the Torch God. The point of this here? Be very careful with large amounts of Torches when you have not yet won against the Torch God.
Another reason for Campfires: They give some life regeneration, which can help in boss fights. If you can afford it, Heart Lanterns can be placed around. Should you opt to do as such, the best layout would be adding two solid blocks horizontally beneath the platforms each campfire’s occupying, perhaps every other campfire if you wish to conserve the heart lanterns. The heart lanterns and campfires will both give a separate buff that increases life regen, and they will stack when both buffs are active. However, only one buff from each furniture item can be active, for example, two Campfires will not increase life regen any more than a single campfire. I mean, it can make you feel better I suppose.
Now, finally get to the tips.
*As mentioned earlier, the Unholy Arrows from Corruption worlds will help in future encounters due to their piercing effect and no other piercing weapon has been obtained. Piercing is so useful due to the Servants of Cthulhu, as they could block the projectile from reaching the boss.
*The Diamond Staff is possibly so early-game that it is obtainable within the first few days if you’re lucky, however it is very useful, especially due its piercing effect and relatively high damage for such a simple recipe:
Eight Diamonds
Ten Platinum Bars
There is one very large drawback…. it CANNOT be crafted from Gold instead, unlike most recipes that use Platinum. This means, if Gold is in your world, you will need to fish or use the Extractinator. The former is simpler, as all it requires is a Wooden Crate to appear, and your own luck for Platinum to be inside. Crate Potions, combined with Fishing Potions, and further with Sonar Potions, make this very easy.
*However, the best thing you can do in a relatively small amount of progress from here is two words: Star Cannon. The Star Cannon is very useful against many bosses, including the Eye of Cthulhu. Very high damage relative to other ranged weapons in its area of progress, combined with unlimited enemies it can pierce, and topped off with a very high fire rate, it is one of the best weapons to get as soon as you can in the early stages of the game. By “as soon as you can” I should probably specify the basics. You don’t need any direct drops from the Eater of Worlds/Brain of Cthulhu, however they must be killed to obtain it, as that is when meteorites fall and this crafting recipe is possible:
One Minishark, sold by the Arms Dealer
Twenty Meteorite Bars, smelt-able from Meteorite
Five Fallen Stars, which often fall from the sky at night to positions near the player.
However, be careful of ammo, as given the very high fire rate combined with Fallen Stars themselves being the ammo, you will easily run out unless you carefully aim, also quite difficult with such high fire rate.
* Accessories. Yellow Horseshoe Balloon is very nice, however it is only obtainable after at least one Goblin Invasion has been defeated, likely far later than this boss will first be encountered. This could be bypa*sed if you are desperate by combining all its parts, however this takes 3 out of 5 (6 in Master difficulty) accessory slots. Instead, you should perhaps bring the Sandstorm in a Bottle, as it is the most useful mobility-wise of the three components. As I mentioned earlier, if you have defeated the Eye of Cthulhu previously on Expert or Master, and the Shield of Cthulhu dropped, use it. It incredibly simplifies the fight, and all fights after up until the very end of the beginning. The reason is not only the small amount of bonus defense, it also features a charge attack that’s pretty much the humanoid-affected-by-gravity equivalent of the Eye of Cthulhu’s charge attack (see the Basic Attacks section if you are wondering about this and skipped ahead and/or forgot). It makes you rapidly move forward a small distance and collide with anything that happens to be in the way, dealing it damage should it be a foe.This has its most basic benefit in added mobility-all you must do is double-press either the A button or D button to charge. This will not decide what direction-the way you face will. This is possible by, for example, holding down the A button then double-pressing the D button, and vice versa. In given example, the charge will face left despite the D button, which is the button for right inputs, being used to trigger it. Again, if you somehow obtained the Zoologist, she helps in another way, as the Guide to Critter Companionship will greatly help with using the shield, as it prevents you from colliding with critters in the way-useful in a couple of possibly serious situations without it even past your days of the Shield of Cthulhu…
*Another must-have is the Frostspark Boots. You can upgrade it to Terraspark Boots, but the only advantage the latter has is walking on liquids (at least, a*suming so given its crafting recipe), and unless you are caught in a completely unplanned location, that is not very useful. The Frostspark Boots, however, have all the non-liquid-related beauty of the Terraspark Boots without the frustration of obtaining Lava Waders to upgrade. Alas, despite how glorious the mobility-related power of Frostspark Boots may be…….you also need a Goblin Invasion to defeat to craft them. If you happen to bring a Tinkerer’s Workbench from another world, or bring the items that require the bench which you desire from said world, you can have the boots or other item. If you do not have access to the Frostspark Boots, you can use some Hermes Boots in the meantime.
*As for armor, Platinum or Gold, depending on what is present in your world, is probably the least you can do while standing a good chance. Molten armor before the fight is rather overkill in Cla*sic, however it can help with Expert and especially Master fights. If you’re lucky, you may have a Warding prefix to an useful accessory, that small boost of defense will go a long way. Quick prefixes can help, but not as much as Warding. If you have magic, then Arcane could help if you not yet have max mana, and if you especially focus on magic, it will help either way.

The Actual Tips

That was so much I couldn’t even fit it. Now time for, well, what the word “tip” means.
*Should you use the Shield of Cthulhu (previous sections), use its dash attack to avoid attacks, not for an actual attack, as it is far more useful against bosses for dodging.
*Melee weapons are typically very poor for this boss, given its flying, pa*sing through blocks, and good contact damage if you stay in it too long, and should only be used with extreme caution, especially on Expert or Master, as it can easily get a good chain of attacks in with the super charge thing during its second phase (see “Basic Attacks” for more info). For optimal use of these short-range weapons, use size-improving prefixes such as Legendary (which is actually the best one on most melee weapons) or Large (which makes it larger than Legendary would, but comes with no other benefits). NEVER, even if the weapon itself is VERY good, use ANY negative modifications against this boss, ESPECIALLY TINY. When I was testing, the Platinum Broadsword I crafted specially for this guide happened to come with Tiny, and I couldn’t even hit the boss ONCE with it while still avoiding contact damage.
*Even with more than enough preparation, remember that focus is just as powerful as weapons and armor. Pay close attention to the boss’s movements along with your own, especially on Expert or Master, so that you may predict where it will move and attack from, and prepare to dodge and/or shoot. Do not slack off, even post-Moon Lord gear and a perfect arena wouldn’t make you invincible. That’s what Journey Mode’s Godmode is for.
*Just like with any boss, unless you go very overkill, health regen alone will not suffice for your healing needs. Bring the best type of health potion available, and the best mana potions you can if you use magic weapons or a large amount of summons (next tip).
*Defeating the Brain of Cthulhu/Eater of Worlds gives access to a very large amount of powerful gear, even the Star Cannon (previous section), and the feat is not too difficult and can be easily done without slaying the Eye of Cthulhu beforehand. The latter also goes for Queen Bee (by the “without slaying the Eye of Cthulhu beforehand” part, anyway), who, given her loot and rewarded Witch Doctor NPC are must-haves for anyone focused on summoning, can be very useful to kill beforehand if you are such a summoner. However, especially on Master, she is FAR more difficult than any of the other mentioned bosses, even the Eye of Cthulhu itself. Still, if you manage it, it will greatly empower an early-game summoner.
*If you do happen to have defeated your evil biome boss (Brain of Cthulhu for Crimson or Eater of Worlds for Corruption), their gear along with the meteorite gear they make available can be extremely bolstering in further battles against them and other bosses, including the Eye of Cthulhu.
* Even if you would prefer to focus on melee weapons, bring at least one ranged weapon. If you want to solely use melee-capable weapons, the Starfury can be an amazing alternative, as it not only is a great melee weapon, but will also cause stars to fall from the sky as projectiles aimed exactly where your mouse was at the time of clicking. The Starfury is also extremely easy to obtain with a blend of luck and patience, as all you must do is search for a Floating Island and loot the chest. Even if you find a different special piece of loot, the other possibilities are just as powerful-the Fledgling Wings are great for mobility, and the Shiny Red Balloon is pretty good if you don’t encounter the wings-but if you do, just use the wings instead, as they will give you just as large a boost to jump height whilst granting you slow fall-very good for avoiding attacks if you time it right. Keep the Shiny Red Balloon, though, as it can later be upgraded with a Sandstorm in a Bottle then further upgraded with the Lucky Horseshoe to create a Yellow Horseshoe Balloon, one of the greatest for relatively early-game mobility.However, don’t fret, there are several Floating Islands in each world, and the exact amount more than likely increases on larger world sizes.
* Remember, knowledge is one of the ultimate advantages, you should use equipment layouts that you can use very well. Whether you like to combine Bee Armor with the Pygmy Necklace and Hornet Staff to unleash wave after wave of stingers, or prefer the simple beauty of a Necro Armor set with a Minishark and Tendon (or Demon) Bow, you will typically be more powerful with what you are experienced with using rather than more powerful implements that you have no knowledge of utilizing to your best advantage.


It has been a long journey, at least for me writing this guide over the past few days, and even if you skimmed through, possibly even skipped to the very end right here, I appreciate you checking the guide out. As you may notice, this has been extremely focused on PC gameplay, and have my apologies. I do not have much knowledge of the other platforms. The arena “screenshots” and branding image both were hand-made by myself using the Snipping Tool app, and thus they may be hard to see or rather unprofessional. Again, I apologize. If you were truly here to gain insight in your mission to defeat this boss, I truly hope and believe you can succeed, as long as you never give up. In this game and in other games I play, I often have lost hope, and thought I would never reach a true amount of progress. While this despair has not been fully averted for me quite yet in Terraria, I have overcome and gotten farther than I had ever imagined before, and I hope you can do the same. Go on, and do whatever you can. You WILL have success, whether tomorrow or in three years, you will.

Written by cjgamer0724

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