Top 10 Hardest Terraria Bosses

Will destroy you if you are not ready. Fast and brutal attacks, with a fun but difficult second phase with ramped-up attacks to follow. The wings and drops are very much worth it though, and there is even an optional enraged mode you can fight the Duke in if he is summoned too far away from the ocean.
Yes I know he's hard I go on normal mode he's (of course) easy. I have the meowmere and it was (again) easy but I still had a friend with me. My friend and I defeated the pillars and then come the moon lord. Even on easy mode with the best sword in the game, full heath, and a friend with the expert type of the best yo-yo and we didn't get the moon lord to half heath when we both died. When we fought fishron my friend died first but I got the final blow and we defeated him in a matter of minutes.
Travel through walls and cannot camp it out without dying if not using a slime statue farm. You need wings and titanium armor instead of chlorophyte or hallowed in case you failed to dodge one of his dashes. Together with the hardship of catching his summoning item, he is easily the hardest boss in the game even beating the moon lord who you can farm easier.
I've fought him three times now and I had the Solar Eruption AND full Solar Armor on me. I also had the Cosmic Car Key but even with that he is just too fast to get around. Every attack is simple to get around but the dashes are simply unfair. The Moon Lord is a breeze compared to this guy.

Literally the final boss. Stupidly high HP pool, uniquely annoying attacks and loaded skillset makes for an overall hard fight. Can also be cheesed with Nurse, however.
Endgame boss, high damage, the eyes are very hard to dodge. Without a nebula or vortex armor, you may find it very hard to kill with a nebula blaze or vortex beater. A solar eruption is useful if you want to beat it easier. When fighting him, make sure to keep the percentage of his eyes similar, and destroy them at about the same time so you can beat the heart straight afterward.
Moon lord definitely is the hardest boss. I had to cheese him multiple times before I got a good enough weapon to fight him with. As for duke fishtron, it is extremely easy as long as you have the right arena. (Asphalt on the floor, campfires and heart lanterns). As for enraged duke fishtron, I killed him 26/27 times without a proper arena. It was only after, when I smashed him in expert mode, did I realise that he was enraged.
The Moon Lord is annoying in a way that it makes you lose almost every single time. It's almost impossible to beat without the Solar Eruption, and you actually require an arena or just a roof to avoid them damn lasers. Overall, the most prestigious boss in Terraria. Duke Fishron has seen better days...

They seem easy, but will kick your ass if you aren't ready. Spaz's second phase is pretty rough, but he follows a set pattern which is fairly easy to predict, but difficult to avoid due to Spaz's chronic strafing habit. Ret will avoid getting close, so consider bringing a ranged/melee hybrid to take out Ret and Spaz. Overall a very fun boss fight with a surprisingly good theme.
Hardest mech boss by far. Some people think that skeletron prime, or even the destroyer is the hardest, but the other two are relatively easy with a good strategy. With the twins, you need quick reflexes, precise aim, high mobility, strong weapons and armor, lots of buff potions, a carefully thought out arena, powerful accessories, the best modifiers, a bit of luck and a lot of practice. Doesn't help that you HAVE to actually fight this boss to progress through the game. Still a fun and very creative boss and he remains a fun boss to fight post-plantera due to his difficulty level.
Most players would choose to defeat the destroyer first. Then it is not that hard to defeat since you are most likely to have the mushroom spear and can hide behind walls for its first stage.
Damn, these guys are hard. The strategy is, you gotta take out Spazmatism first then get Retinazer for an easier fight. Spazmatism is way too hard at Phase 2, but learn his algorithm of attack, and he's not so hard as you think. Retinazer seriously is uhhh, not too good. It won't take much effort to beat, as long as you avoid the lasers.

Difficult due to the amount of contact damage she deals and the grabbers she unleashes during her second phase. Many players also break the bulb accidentally, spelling an early doom.
Remember to clear the terrain and be prepared when fighting it for the first time, or you can hardly do any maneuvers in the jungle. It is a large boss with high damage. You can hardly kill it with melee weapons besides spears at that stage of the game. Your bullets are easily wasted since its hitbox is not as large as its reach. You don't even have a raven staff as a summoner and there is no corresponding class set up by the new ores you mine.
Try magic weapons for best.
Use teleporter on 2 sides of an arena and make a wall of any block to block mobs from spawning in on the side of the wall. You can then shoot it with a bow or gun whichever. Add campfires and heart lanterns. I could barely beat it this way!
Plantera is reasonably easy, I took her out with the scourge of the corrupter and the Terra blade in a mine shaft. That only happened because I have the chlorophyte mask and hallowed armor. The best way in my opinion is the two teleporters and shooting at her through slits. best weapon recommendation is possessed hatchet
Well, this took a long time to defeat! I spent 2 days devising a plan to beat him and it still wouldn't work. I killed the twins for a practice round, because they are pretty easy. I killed him AFTER my friend and I beat the frost moon. I felt weak compared to terraria, but I know that a lot of others feel that way also.
Skeletron Prime has a lot of limbs. Some of them are useful, some of them aren't. He's still strong, but being on platforms basically immobilizes one of his limbs. Just kill the limbs, then kill the bone man.
You cannot farm it since its limbs are hard to deal with. When you find the pattern of attack, it is reasonable. Very hard to fight without the north pole or other later weapons.
Are you kidding me Skeletron was the easiest boss! It took me about 1 minute to defeat him!

Just because it's one of the first bosses doesn't mean it's hard. The Eye will rush you and deal tons of damage (to noobs anyways), which is fairly difficult to avoid if you have no movement speed items. In Master mode, Eye's skillset is buffed with a new spin and blitz it does when below half, and this is difficult to avoid AND survive.
Eye of Cthulhu was pretty easy, if I beat it I get some red and black ore (I already wasted it on a sword and bow ) that I found in caves. I got somewhere about 24 or less ores. But it was a little annoying since he goes up into the air and I am horrible with the diamond staff so I just waited to use my rainbow claws and I killed him. Took me a total of 2 minutes.
This boss should be easy when you join hard mode. If you are a beginner or started a new character it would be best to fight king slime before you fight the eye of cthulhu. It is recommended to have a musket with a couple hundred bullets and at least 10 defense points.
The eye of Cthulhu is extremely easy. I beat him first try with wood armor and a tungsten sword. I would say this boss is easy, and if anyone isn't able to beat it, they are not good at game.

Pretty hard, but not too hard. If you come in with hardmode gear he's the easiest thing ever, and even pre-hardmode is still pretty easy. However, if you're not prepared you are going to struggle with this boss. I recommend getting a minishark and molten armor.
He was so easy I had a physician skull water walking boot combo and had ended up with a glitch world where I went above 0 level in the dungeon before killing skeleton and found a rainbow gun in a normal chest took me 10 seconds.
Difficult usually due to lack of platform bridges in hell and demons sniping you with spells.
Well, I beat him with 11 golden hearts and a titanium sword, not as hard as I thought.

People are RETARDED! "I beat him in 20 seconds, and all I had was end game weapons and armor, fighting a pre-hard node boss! ". This should be for what you WOULD have at a certain stage of the game that the boss is found!
Bruh this is easily the hardest boss in the game. I think it is literally impossible to beat and definitely needs to be rebalanced. If it is even beatable does anyone have any tips on beating this monstrosity.
Not so hard I mean it's a giant slime just it has a ninja and crown, oh and it also does s butt load of damage. that's why I hate all the bosses they make me use a greater healing potion then they attack me and then I can't use the potions and then I DIE!
The hardest boss ever. It makes the game unfair and impossible on how good it is. Make this boss easier in version 1.4 please. 1 vote= one vote for easier King Slime!
It used to be in the Mobile version of terraria so I know. It has a lot of forms of attack and is hard to dodge. It easily kills a player in hallowed armor if he is not dodging properly. The summoning item was expensive to make.
With complete turtle armour the Terra blade wings and a twenty by twenty box around you he's easy I've beaten him 13 times and I've spawned him 13 times so...
Not that tough. I beat him with a Nights Edge and Adamantite Armor.
Ocram is just a palette cleanser, kinda like Sally Stageplay from Cuphead.

Whilst Golem is easy, King Slime is miles easier.
For starters, King Slime is the very first boss you fight, whilst Golem is one of the last bosses you fight.
Then there's the fact that King Slime can be cheesed by building 30 Ropes up into the sky and throwing shurikens down at him.
I have dragon armour and the terra blade and I still can't take him out when everyone says he's easy. I got up to level 10 with the pumpkin moon but I can't beat him?
Easiest to farm although it might be a bit damaging and tough. Its attacks are very simple to observe and dodge.
He is hard because he shoots eye beams that do a lot of damage that almost kills me and I have 31 defense.

Really deserves to be under Duke and Moonlord in terms of difficulty, but this guy definitely at least deserves the number 3 spot. If you don't have a proper DPS weapon for the cultist himself as well as a decent weapon that can simultaneously attack the segments of the dragon he conjures, you'll find yourself gobbled up pretty quick.
The second latest boss by progression, however, is not as hard since you can build barriers and beat it easily. You can also parry his magic attacks easily. Mind the dragon.
What? Why is he so low on the list? Golem plantera and twins were super easy and I did them all on my 1st try except this one... Am I doing something wrong?
Dude, I have 53 DEFENSE and he's still the hardest other than Fishron, Prime and Twins.
Not too difficult, but the enclosed underground spacing will make for decreased movement for you, and the creepers will be able to hit you easier. Fighting above ground is usually what I do, as it requires less preparation and manueveration.
Is a complete joke with multi-hit weapons like the starfury. Without them? He's a total pain. Just keep getting better armor and more hearts and you'll eventually beat him.
How is this easier than a green slime?
How do you defeat thi?
Somewhat difficult, probes can provide decent ranged support for The Destroyer while it pursues you, so just let it loop you and use a fast melee to clap it.
I play on Xbox 360 so I'm not sure if this works on other platforms but he's my story anyway. I just couldn't beat him, I had the best armor available at the time and I just couldn't beat him. I found out the hard way that the cobalt sheield helps a lot. Just stand still and swing your sword. The destroyers body will come to you dealing contact damage every time your invincibility wears off from being hit but the drones he spawns will die from the sword giving you hearts. So easy now. Can kill 27 in one night now.
Well, very tough, very damaging and annoying, but its attacking pattern is so simple that you can just build a platform and cut it off with your night's edge, which is a pre-hardmode weapon.
It took me a long time to beat, but the Destroyer gets DESTROYED by the Daedalus Stormbow or other weapons that do multiple areas of damage. Just learn the attack algorithms and it'll be easy.
Hard without right gear, which is grenades, jester arrows, or water bolt. Be wary of it splitting up.
I literally just swung my sword and took it out first time. Loss 1 heart
Easy to kill in my world
I have 9 bee hives in my game and I didn't take one hit with my megashark she was so easy I tried with a cutlass still beat her this is too easy.
Hard as hell when you have no strategy.
I defeated 10 in 1 day!
It was hard for me, I was in expert mode and had full Molten Armor and a Nights Edge.
In normal mode he's a joke. In Expert? It's a nightmare.
He is easy I kick his butt with a nights edge and wood armor. he is a good thing to get the dryad
Hardest in expert mode

Real tough boss. Although only a mini-boss, the ice queen is really had to beat and doesn't guarantee a good drop, making its single defeat a low yielding work. It is even more annoying after 12 waves of the frost moon, as you may see a couple of these at the same time.
Easier than green slime

Dint get me started
I found him hard
It is so scary
Difficult because of its progression, which is post golem, and the fact that it spawns after a large wave, and there is another objective of protecting the crystal as well.
Best pre-Moon Lord drops in my opinion.

BUTTERFLY LADY! All jokes aside, this femme fatale will rock your world at nighttime if you aren't prepared or underestimate her. She has a large moveset and is fairly fast, but makes up for it by having many telegraphed attacks. Summons will take her out fairly easily if you keep good range and focus on avoiding her light beams. Daytime is basically the same story albeit with probably a larger arena needed and a complete focus on speed. Easier with friends.
The Empress of light is insanely OP during daytime- I had to find all of the pieces of Zenith to defeat her. She can kill you in 1 HIT, dodge attacks REALLY well, and it might just be my gamma settings but her light attacks are IMPOSSIBLE to dodge. if that's not hard to beat then I don't know what is.
If you think the empress of light is an easy boss, you've got another thing coming.
Although she is easy as to defeat at night, daytime gives you different loot and more to brag about. don't let her sparkly rainbow guise fool you.
Just use muramasa
Who else got reminded of spongebob?