Thorium Mod Wiki
The Queen Jellyfish
The Queen Jellyfish
The Queen Jellyfish.png
AI TypeThe Queen Jellyfish AI
Damage25 / 50
Max Life4000 / 5500
KB Resist100%
Inflicts debuffBubbled.pngBubbled
Debuff duration1 second
Debuff tooltipYou're floating away!
Immune toCrowd Control.pngPoisoned.pngVenom.png
Coins30000*3 Gold Coin.png
The Queen Jellyfish (Diverless).png
The Queen Jellyfish after defeating it once

The Queen Jellyfish is a Pre-Hardmode boss available in the Thorium Mod, summoned by using a Jellyfish Resonator in the Ocean during the day. The boss summons a large number of Royal Jellies throughout the battle, making it tricky to fight with without proper preparation. The following are some hints, tips, and strategies to help defeat it.

Terrain Preparation[]

While it is entirely possible to defeat the Queen over the open waters with a Water Walking Potion or Water Walking Boots, it is recommended to create an arena to fight over. One possible option would be to lay a line of around 120 Platforms, with a vertical tower of either platforms or Minecart Tracks – about 20-30 blocks in height – every 30 blocks; these towers will serve as catchments for your Grappling Hook to allow for quick getaways from some of the boss's attacks.

The arena can also include Campfires, Heart Lanterns, Star in a Bottles, and Sunflowers to give the player increased life regeneration, mana regeneration, and movement speed for the encounter.

If you are using a weapon that utilizes a projectile that bounces off blocks, such as the Yew Wood Lute or Water Bolt, you may wish to line the area above the arena with solid blocks to allow such projectiles to bounce back into the fight, increasing your damage output.

Gearing Up[]


By this point of the game, each class has a dedicated armor set that provides bonuses for a specific damage type. However, should you be using a variety of weapons of differing types, there are some other sets that you should consider. Thorium armor is a strong choice, offering a 10% increase damage for all weapon types. Steel armor is easy to acquire, and its increased damage reduction helps if you find yourself unable to dodge many of the attacks from the encounter. Crimson armor, similarly, heavily increases the player's life generation. Flight armor is a fantastic choice in terms of maneuverability, as its set bonus grants the player a set of Wings. Finally, if you are playing with a group, the Depth Diver armor grants buffs to all players nearby, making it worthy of consideration.

If you are playing as a Warrior, the Shadow armor is a good choice, especially if you are using a Yoyo, as the increased melee speed translates to increased yoyo range, allowing you to attack the Queen from a safer distance. If you are in a world with the Crimson instead of the Corruption, you should aim for Magma armor, crafted from Magma Bars. It does not increase your melee speed, making it more risky compared to Shadow armor, but its set bonus of increasing the effectiveness of On Fire! and Singed makes it a more offensive counterpart.

If you are playing as a Ranger, the Yew Wood armor and Tide Hunter armor sets are the only ranger-specific armor available at this point of the game. Despite the Tide Hunter armor being acquired later within the Aquatic Depths, the Yew Wood armor is slightly more suited for the fight; its increased firing speed and mini-crits lets it deal more damage over time compared to the Tide Hunter armor. The Tide Hunter armor, on the other hand, has slightly more defense and critical strike chance, and its set bonus allows you to slow and more easily deal with the Royal Jellies.

If you are playing as a Mage, you should aim for either Jungle, Bulb armor, or – if you have managed to complete the necessary contractsMalignant armor. The Malignant armor, in particular, does not require a leggings to obtain the set bonus, allowing you to use any other armor leggings. The Jungle Pants provide the best magic bonuses at this point of the game. If you wish to use the Space Gun for this fight, be sure to equip Meteor armor for its set bonus.

If you are playing as a Summoner, the best armor set available is the Astro armor. This armor is especially good against The Queen Jellyfish as its set bonus gives minions a chance to create an explosion of plasma on hit, which is fantastic at cutting down swarms of Royal Jellies.

If you are playing as a Thrower, while the boss is entirely possible with Sandstone armor, you should use the Fossil, or at minimum, the Ninja armor, as it provides a wide range of throwing boosts.

If you are playing as a Healer, the strongest armor set that is available at this point is the Iridescent armor, unless you have defeated Skeletron.

If you are playing as a Bard, unless you have explored the Underworld, the strongest available armor set is the Jester armor. Its set bonus, while not affecting the Queen itself, does slow the Royal Jellies, making them easier to deal with.


Spectre Boots, along with its upgrades Lightning Boots and Frostspark Boots, are a fantastic accessory for improving your dodging capabilities for the fight, allowing for increased horizontal and vertical movement. Other options include Mana-Charged Rocketeers, Traveler's Boots, or Survivalist's Boots. If you have a spare accessory slot, the Mana-Charged Rocketeers provide nearly infinite flight for players not utilizing mana. One of the attacks from the Queen launches the player high into the sky, so accessories that reduce the damage taken from falling may be worth considering if you have difficultly recovering from it. While the Lucky Horseshoe and its potential upgrades offers complete damage nullification from falling, if you do not have one other options include Spring Steps, Frog Leg, or a Cloud in a Bottle. The easiest solution, however, is to simply use the Spectre Boots's flight or to grapple onto a platform.

A Ring accessory is useful for the multiple buffs it offers. At this point you should be able to craft The Ring, which combines each of them, making it quite the powerful choice. The Crietz is able to quickly shred health given ample amounts of critical strikes.

If you are playing in Expert Mode, the dash from the Shield of Cthulhu is highly useful for the fight. Aside from allowing the player to quickly dodge past the boss when turning around, it is also helpful for removing any Royal Jelly in your way. Additionally, the Worm Scarf offers damage reduction, which may be helpful to take some additional hits throughout the encounter.

Melee players should equip a Yoyo String, as the increased range will significantly reduce the danger you will be by being within close proximity to the boss, as well as helping remove Royal Jellies. A Counterweight is very useful for yoyo users as well. Feral Claws are worth considering, but only if you are using a sword (not recommended unless it has a projectile).

Throwers have a variety of options to use. The Guide to Expert Throwing offers a decent increase to your throwing damage, but can be replaced with either the Bone Grip or Spartan Sandals, as they offer more throwing benefits.

Bards, similarly, have a wide range of options to consider for the fight. The Mouthpiece allows for your wind instruments to home in on enemies; while later in the fight this is actually detrimental due to it attempting to attack the Royal Jellies instead of the boss itself, it is perfectly usable in the first half where there is less minions summoned, and can inflict large amounts of damage when switching directions, when it runs into multiple homing projectiles. The Plunger Mute suffers from a lack of good weapons at this stage of the game, but if you have the Hot Horn, the spark spread is helpful for clearing away swarms of Royal Jellies. The Guitar Pick is of little use in a large open area needed for this fight, and the Vibration Tuner is not available unless you have defeated Skeletron. The Mix Tape provides a decent Singed debuff, which helps deal damage when you are regenerating your inspiration; Marching Boots or its upgrade can help with this. Other options for the fight include High Quality Reed, Pad o' Paper, or Music Notes.


In general, piercing weapons are excellent for the fight, due to the sheer number of Royal Jellies the boss summons throughout the battle.


Many melee weapons are impractical against The Queen Jellyfish, due to the long-ranged nature of the battle. Despite this, there are still a number of options.

Swords should be limited to a sidearm for the fight, as its swing arc makes them great for clearing away any Royal Jellies in your way. For that purpose, ones with large sizes are preferred, such as the Phaseblade or the Blade of Grass. The Blooming Blade is also decent for this encounter, as it has a fast swing speed and provides the Life Recovery buff on hit, granting the player minor increase to life recovery.

Swords should only be considered for fighting The Queen Jellyfish directly if it is capable of firing a projectile. The best option for this is the Starfury; the falling star from it is capable of piercing up to 2 enemies, making it helpful for defeating the Spitting Jellyfish that hover above the boss as well as the Queen itself. In addition to this, it deals large amounts of damage, and the swing from the sword still inflicts damage, allowing you to simultaneously damage both the boss itself and any Royal Jellies attempting to ram into you. The Bellerose is also a good choice for a more direct beam-shooting weapon, although it requires Obsidian and therefore, requires a Nightmare/Deathbringer Pickaxe or Reaver Shark.

Spears are not recommended for the fight. They are simply too slow to effectively deal with the numerous Royal Jellies, and not long-reaching enough to combat the boss itself without putting yourself in danger. Even with a Spear Tip equipped, they do not deal enough damage.

Due to the number of Royal Jellies summoned to shield the Queen, Boomerangs are not particularly useful for the boss itself. That said, it is still recommended to use one as a sidearm to throw whenever the opportunity presents itself, whether to thin the number of Royal Jellies or to inflict additional damage against the boss itself. The Danger Doomerang allows you to throw 2 boomerangs at once and the Magmatic Reflector inflicts the Singed debuff.

Due to their piercing properties, Thrown Flails are not a horrible choice, however if you choose to use one, you need to place solid blocks below your platform floor, else they will pass through and take significantly longer to recollect the flail head. The main options for this point of the game are the Ball O' Hurt or The Meatball (depending on if your world's evil is Corruption or Crimson), and the Magma Flail.

Yoyos are the best option for melee users against The Queen Jellyfish. With some items to boost their range, you can comfortably inflict large amounts of damage against the boss without putting yourself in serious harm's way, and the ricocheting yoyo head will often take out any nearby Royal Jellies, such as the ones immediately spawned. Their only inconvenience is dealing with Royal Jellies that were able to evade your attack at try to ram into you; for that carrying a sword or boomerang for them is recommended. Malaise, Artery, Illustrious, and Aerial are all excellent options. The Aerial is a particularly good option, as it summons eight feather projectiles in the eight cardinal directions occasionally, dealing a lot more damage than a non-projectile yoyo. If Viscount has been defeated before the fight, the Bat Wing is a great yoyo due to its long range and its homing bat projectiles, but the lack of projectiles overall makes it more difficult to use.


Ranged weapons are excellent choices for this fight, as many of the weapons and ammo feature long range and piercing capabilities.

For Bows, some options include the Yew Wood Bow and Feather Foe. The Talon Burst, dropped by The Grand Thunder Bird, is a decent option with armor penetration, such as from a Shark Tooth Necklace, as its Storm Bolts allow to hit a foe twice. However, it does not pierce, hurting its effectiveness in the later stages of the battle. The Danger Dual-shot fires 2 arrows at once, making it potent at clearing swarms of Royal Jellies when paired with an arrow that pierces. As such, the main choice of arrow should be between Ocean Arrows and Jester's Arrows due to their ability to pierce. Ocean Arrows have a chance to inflict the powerful Gouge debuff, which has the added benefit of ignoring the Queen's damage reduction during its cyclone attack, while Jester's Arrows are unaffected by gravity and have no limit to the number of enemies they can pierce.

Guns are also viable options. The Yew-Handled Flintlock is easy to obtain and has a high firing speed and good damage. Either the Minishark or the Shark Storm are good options due to their high DPS and auto-firing properties. At this point, the only bullet with the ability to pierce enemies is the Meteor Shot. As they can also bounce off blocks, it is a good idea to surround your arena with blocks to take advantage of this.

Similarly to the Minishark, the Aqua Pelter has a high firing speed, auto-fire, and does not require ammo to fire. However, it does not pierce, making it only fantastic for the beginning stages of the battle. Though the Webgun cannot pierce, its projectile creates a damaging area of effect web on hit. If you manage to continually hit The Queen Jellyfish, the Royal Jellies spawned over it will often immediately be removed due to the web. If you cannot locate one, the Spud Bomber is a more-easily obtained option that still does decent damage. Lastly, The Zapper is not particularly useful against the boss due to its sub-par DPS, but its instant transmission and piercing makes it excel at picking off any Royal Jellies, especially Spitting Jellies.


Similarly to ranged weapons, Magic is a good option as well. Many of their weapons have long range and some degree of piercing, but has more options for covering a large area in exchange for having to handle mana. This is not a major issue, however, as many mana-restoring Stars will drop from the Royal Jellies.

The Magick Staff, though weak in terms of damage, has several properties that makes it a great weapon to use, boasting piercing, several debuffs such as On Fire! and Ichor, and life steal. The Thorium Staff does not pierce, but inflicting damage will fire 4 additional homing projectiles, which will go to either the many Royal Jellies or the boss itself. The Crimson Rod is great as a side weapon to use once in a while, inflicting damage over an area; you can summon the cloud over the boss when it is doing its cyclone attack for free damage. Its counterpart, the Vilethorn, is not as useful, but its piercing makes it good for clearing away Royal Jellies. The Shadowflame Staff is recommended, as it pierces all enemies and inflicts Shadowflame. Its slow velocity, however, means some practice will be needed to lead the shots into the boss. Finally, the Blooming Staff is a phenomenal weapon in terms of DPS thanks to its high damage, firing speed, auto-fire, and Life Recovery buff.

Another piercing weapon is Wind Gust, sold by the Desert Acolyte, being cheap to purchase and reforge, and having a larger than average hit box size. Water Bolt, if you find it in the upper sections of the Dungeon, is similar, but deals slightly more damage and can ricochet off blocks. The Dark Tome from the Dark Mage's Treasure Bag is costly in mana usage, but similarly to the Petal Wand, is powerful enough to rip through The Queen Jellyfish's health.

The Magic Conch is very useful if you have ventured down to the Aquatic Depths before fighting the boss, but it might prove difficult to obtain.

Lastly, the Space Gun, especially if you are using Meteor armor, is a very solid weapon, with a high shot speed, auto-use, and slight piercing properties. It is fairly costly in terms of mana usage without the Meteor armor, so if you are using it without the armor set, try and defeat as many Royal Jellies as you can to keep a solid amount of mana-restoring Stars close by.


As most minions inherently pierce enemies, Summon weapons are fantastic against The Queen Jellyfish.

For the encounter, minions capable of flight are preferred, due to the floating nature of both the boss and its spawn. A good option for this is the Meteor Head Staff. The Living Wood Acorn is not very useful, as its damage is sub-par and cannot pierce. Despite this, there is little reason to not use it, as it does not cost a minion slot and can provide minor support.

It is highly recommended to clear the first tier of the Old One's Army before fighting The Queen Jellyfish, as it allows the player to use the Tavernkeep's Sentries outside the event. Of the 4 available options, the Ballista Rod is the strongest choice, boasting high damage and piercing. Though slow to reload, it fires as soon as it is summoned, meaning by rapidly re-summoning the Ballista, you can significantly increase the damage output. The Flameburst Rod is not a terrible choice but, in comparison to the Ballista, lacks vertical aiming, damage, and piercing. Its splash damage makes it potentially useful against the Royal Jellies, however. The Explosive Trap and Lightning Aura Rods can be used to clear out swarms of Spitting Jellies, but if you wish to do this, you should extend the width of the arena's vertical towers to make it easier to place the sentries on them.

If you do not find the Tavernkeeper, there is another way to use sentries without the Tavernkeep's Sentries. The Creeping Vine Staff is an excellent choice for this fight due to its ability to attack enemies within the range of the sentry, making it pretty useful for the fight. If your world is in Crimson, the Bleeding Heart Staff is a good choice as it will double the fire rate when enemies are damaged by its sentry by five or more. If your world is in Corruption, the Devourer Staff is an excellent choice as it cracks the egg into 4 tiny eaters which home in on enemies, making it pretty useful against its boss and jellyfishes.


Due to the number of minions, the best choice for throwing weapons should be some variety of Knives due to their piercing. Of these, the best choice by far are Aquaite Knives; they possess phenomenal DPS, can auto-fire, and their ricochet allows them to either defeat nearby Royal Jellies or nail additional hits against The Queen. If you do not wish to venture into the Aquatic Depths until after the boss fight, Frost Daggerfish or Bone Throwing Knives are alternatives that are still solid.

If you have cleared away all Royal Jellies and have a clean shot towards the boss itself, a Javelin may be better suited for its better single-target damage. Goblin War Spears have a chance to inflict the powerful Gouge debuff, shaving large amounts of health, even when The Queen Jellyfish's damage reduction is raised during its cyclone attack. Bone Javelins are even better at this; the individual weapon deals higher damage, and while the Penetrated debuff is not as strong as Gouge, it is more consistent to inflict and lasts for a longer amount of time, making it's overall DPS higher.

Explosives offer the very real possibility of blowing yourself up in the splash damage, especially given the number of Zealous and Distracting Jellies attempting to intercept you, but in the hands of skilled and confident players, large swathes of summoned Jellies can be easily cleared and extreme amounts of damage can be inflicted onto The Queen itself. Bouncy Grenades' higher natural velocity make them the easiest to land against the boss. Happy Grenades are the safest explosives, but are difficult to initially obtain, requiring killing the Party Girl. Sticky Grenades can be stuck onto the vertical tower platforms, making it easier to manipulate the boss to float straight into them.

The final two options to consider are Sea Ninja-Stars and Molotov Cocktails. Despite being unable to pierce, Sea Ninja-Stars possess auto-fire, high velocity and throwing speeds, adequate DPS, and are relatively easy to amass, making them an economic option. Molotov Cocktails, on the other hand, are difficult to obtain, but are fantastic against the boss. They possess high damage, inflict On Fire!, have a acceptable velocity, and unlike standard Grenades, do not run the risk of damaging the thrower.


Healers should, as their name applies, should place highest priority into restoring the health of their allies, or supporting them in various capacities. Of the healing spells available, some good choices include The Good Book, the Eater of Pain or Brain Coral, the Cleansing Water Pouch, the Blooming Wand, and, if you are playing in Expert Mode, the Dark Gift.

At this point of of the game, your options for support spells are highly limited. There are only two choices readily available: Cure, crafted with a Book, Purified Shards, a Bottled Water, and a Stinger; and the War Forger, purchased from the Blacksmith. As The Queen Jellyfish does not inflict any debuffs that can be removed with Cure, War Forger should be your only option. Thankfully, it is a fairly decent option as the player can leave the magical anvil near the center of the arena, and quickly activate it whenever they pass through for some free life shield.

As for radiant weapons, you should mostly focus on ones with range given the nature of the fight. As such, Scythes should not be used for any reason other than helping clear up Royal Jellies. A Dark Scythe, Crimson Scythe, or Aquaite Scythe will suffice for this purpose. The one exception to this rule is the Poison Prickler; with its right-click ability to summon poisonous clouds and auto-fire, it can provide a risky, yet feasible way to defeat the Queen Jellyfish.

Leech Bolt is a fantastic weapon, because its range, piecing, and life steal allow for added survivability to better support your allies or combat the boss. The Shadow Wand is also good, once you are accustomed to its awkward trajectory and can reliably hit the boss. Once you have, you have a weapon that possesses auto-fire and piercing properties, as well as decent damage with the Shadowflame debuff. The Deep Staff, obtained from Scarlet Chests, is stronger than the Shadow Wand, but has a slower velocity and cannot piece, hurting its usefulness. Finally, the Feather Barrier Rod is a good supporting weapon. While it is unable to adequately deal with The Queen itself, it allows players to run into Royal Jellies and take many down as they pass.


Symphonic weapons are great for this battle, as many of them are long-ranged and piercing, making it easy to rack heavy amounts of damage.

The Didgeridoo, while slow in velocity, pierces enemies and has auto-fire. With the Mouthpiece equipped, the pulse will often stay on top of The Queen, inflicting large amounts of extra damage. The Icy Piccolo is a decent option for the first stage of the battle, dealing decent damage and inflicting the Frostburn debuff, but lacking the piercing to make it viable once the boss begins rapidly summoning Royal Jellies. The Meteorite Oboe is worth considering, as the astral clouds the ear worm produces can often damage newly spawned Royal Jellies, but it is expensive to use and the rapid hits will give the boss brief invulnerability that will often let it take no damage from other weapons.

At this point of the game, the only viable Brass instruments require either venturing into the Underworld or defeating Skeletron. However, the Hot Horn, crafted from Hellstone Bars, is a fantastic option against The Queen Jellyfish, making it worth consideration. By leading the flame vibration in front of the boss, you can damage it multiple times and inflict On Fire!. Additionally, it has auto-fire and can pierce.

Due to their natural piercing properties, every Pre-Hardmode String instrument is viable against The Queen Jellyfish. That said, to best take advantage of their bouncing capabilities to better deal with the Royal Jellies, it is highly recommended to line solid blocks above and below the arena. Of the 4 instruments, the Sitar has the highest DPS.

Similarly to Boomerangs, the Ebonwood or Shadewood Tambourines are solid sidearms to throw at either the boss or its summons once in a while. They can even be thrown twice before waiting for their return.

Pre-Hardmode Bosses The Grand Thunder Bird (Map icon).png The Grand Thunder Bird • The Queen Jellyfish (Map icon).png The Queen Jellyfish • The Buried Champion (Map icon).png The Buried Champion • The Star Scouter (Map icon).png The Star Scouter
Hardmode Bosses Borean Strider (Map icon).png Borean Strider • Aquaius, the Endless Tide (Map icon).pngOmnicide, the Life Defiler (Map icon).pngSlag Fury, the First Flame (Map icon).png The Primordials
Classes The Ring.png Class setups • Cleric Emblem.png Healer • Bard Emblem.png Bard
Crafting Arcane Armor Fabricator.png Crafting Quick Reference • Terrarium Defender.png Terrarium Defender