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The Dreadnautilus is a Hardmode enemy summoned by fishing during a Blood Moon. It is one of five enemies that can be summoned by fishing during a Blood Moon in Hardmode, the others being the Wandering Eye Fish, Zombie Merman, (which are also available in pre-Hardmode), Blood Eel and Hemogoblin Shark. The Dreadnautilus is rarer than the other four Blood Moon fishing enemies, spawning from only 10*1/10 (10%) of spawn attempts, on average. It is widely considered the most difficult of these five enemies. If the Dreadnautilus is not defeated by dawn (4:30 AM), it will fly away and despawn.

It is one of the few entities that can be detected by the Lifeform Analyzer or its upgrades.


The Dreadnautilus has the following attacks[1]:

1. Faces away from the player and charges up for 1.5 second, then dashes directly towards player. When it is close enough to the player, it will spin around them. The dash attack lasts 3 seconds, and it will stop dashing/spinning after 3 seconds have passed.

2. Faces towards player and charges up for 1.5 second, then fires three rapid sprays of red projectiles at the player and recoils after each burst.

  • It will not reflect projectiles during the charging phase.

3. Briefly glows crimson and summons up to three "Blood Tears". After 1.5 seconds, a Blood Squid will emerge from each tear, and the tears will despawn after another 1.5 seconds. [2]For more details about this attack, see Notes.

The Dreadnautilus will use said attacks in following sequence[3]:

  • After spawning: 2, 1, 2, 3.
  • Then, repeat the following sequence: 2, 1, 2, 1, 2, 1, 3, 1, 2, 1, 2, 1, 2, 3.


Achievement Don't Dread on Me.png
Don't Dread on Me • Defeat the Dreadnautilus, murderous mollusk lurking beneath the surface of the sanguine seas.
Defeat the Dreadnautilus for the first time.


  • The following are the technical details of the "Blood Tear" summon[4]:
    • The Dreadnautilus will only perform this attack if the player is less than 125 tiles away.
    • Tears will be summoned within a rectangular ring area of 40×40 tiles centered on the Dreadnautilus, except the 16×16 tiles centered on the Dreadnautilus.
    • Tears can only be summoned in the air, water, or honey, with an unobstructed line of sight to the player, and when there are fewer than three Blood Squids currently alive (regardless of whether the Blood Squids are summoned by that Dreadnautilus). Also, the 4×4 tiles area around the summoning location cannot contain solid blocks.
    • If there are fewer than 3 Blood Squids currently alive, then 3 tears will be summoned and thus another 3 Blood Squids will be spawned.
      • As a result, up to 5 Blood Squids can exist at the same time when fighting one Dreadnautilus.
  • There is no limit to how many Dreadnautilus can exist at the same time. It is possible to fish up another Dreadnautilus when one is still alive.


  • The Sonar Potion will detect if the Dreadnautilus is about to be hooked, and can give the player a moment of warning to back away and activate their potions.
  • Using the Chum Caster gives the player a greater chance of finding the Dreadnautilus and other Blood Moon fishing enemies. Using Sonar Potions will allow the player to skip past other Blood Moon fishing enemies and unrelated catches, letting them fight the Dreadnautilus more over the course of the night.
  • Summon weapons are useful for handling the Blood Squids while the player focuses on the Dreadnautilus. The Blade Staff is a great choice due to its defense-ignoring capabilities, and will ignore all of the Dreadnautilus' defense.
  • Inflicting the Ichor debuff, e.g. via the Golden Shower, can be helpful for lowering its high defense.
  • Hiding under blocks is useful as it blocks Blood Squid's projectiles, as well as the red spit projectiles the Dreadnautilus employs.
  • Of the three attacks that the Dreadnautilus employs, only the spin attack will phase through walls, since the enemy itself also phases through walls. A good strategy to cheese the enemy is to build a box and use weapons that can attack through the walls like the Daedalus Stormbow with Ichor Arrows, or use Summons. The spin attack only hits once per cycle, since the AI defaults to spinning around the player without touching them if they stand still, so the player can tank it by using Campfires, Heart Lanterns and honey (and Regeneration Potions and Well Fed buffs if the player is in higher difficulties).
  • Since this fight takes place at night with a possibility of rain, visibility can be an issue and can make projectiles difficult to perceive as the blood-colored rain is too similar in color. Using a Hunter Potion, along with a Night Owl Potion and Shine Potion, will help with visibility.
  • If Blood and Gore is turned off in Settings, the red spit projectiles will be covered and followed by thick white cloud, and it can be harder to distinguish projectiles among the clouds. However, the white cloud can make projectiles more visible during night.
  • When it spins around the player, standing still in the center of it’s spin instead of trying to get out will stop it from damaging you as it only spins in a direct circle.


Scrapped Dreadnautilus Trophy.png
The scrapped Dreadnautilus Trophy in its placed form.[5]
  • If more than one Dreadnautilus' synchronize their attack patterns and they summon "Blood Tears" together, the maximum number of Blood Squids existing at the same time will be increased, which can be calculated by this formula: Maximum number of Blood Squids = 2 + 3 × Number of Dreadnautilus.
  • Despite being officially considered a mini-boss, Dreadnautilus has a lot of similarities to a boss. It is considerably harder to defeat than regular mini-bosses, has complex patterns reminiscent of a boss including spawning supporting enemies, and even its own achievement.
    • Leinfors goes over this in the official Terraria Discord, expressing that Re-Logic had problems deciding whether Dreadnautilus should be an event boss or just a normal mini-boss, with a trophy even being made for it.[6][5]
      • Similar to how other Trophies resemble parts of the slain boss, the Dreadnautilus' unused trophy resembles its mouthparts.
  • It resembles a chambered nautilus, the creature after which it is named.
  • Its name is a portmanteau of dreadnought, a type of early 20th-century battleship, and nautilus, a marine mollusk of the Nautilidae family.
  • Its original name was Blood Nautilus, as seen in the official Journey's End trailer.[7]
  • Re-Logic may have gotten the idea for adding a shellfish boss to the game from an April Fools' forum post by Cenx, stating that a boss called the Conch of Fish would be added, playing off the acronym WoF for the Wall of Flesh.[8]
  • The BestiaryBestiary entry for the Dreadnautilus: "An enormous shelled water demon which feeds off the negative energy of a Blood Moon. Brutally responds to being pestered."


  • Desktop 1.4.1:
    • Chance of dropping the Sanguine Staff increased from 20% to 50% / 100%.
    • Chance of dropping the Bloody Tear increased from 11.11% to 50% / 100%.
    • Now grants an achievement.
  • Desktop Should now properly retarget another player in Multiplayer when the currently targeted player dies or teleports away.


  1. Information taken from the Desktop version Desktop source code, method AI_117_BloodNautilus() in Terraria.NPC.cs.
  2. Information taken from the Desktop version Desktop source code, method AI() in Terraria.Projectile.cs.
  3. Information taken from the Desktop version Desktop source code, method AI_117_BloodNautilus() in Terraria.NPC.cs.
  4. Information taken from the Desktop version Desktop source code, method BloodNautilus_CallForHelp() in Terraria.NPC.cs.
  5. 5.0 5.1 Leinfors' message in #terraria-chat on the official Terraria Discord server (link to message) Sep 17, 2021
  6. Leinfors' message in #terraria-chat on the official Terraria Discord server (link to message) Sep 17, 2021
  7. Terraria: Journey's End (0:50) June 10, 2019
  8. Duke Fishron and The Aquarian Horde! April 1, 2014