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Desktop/Console/Mobile-Only Content: This information applies only to the Desktop, Console, and Mobile versions of Terraria.
DreadnautilusHardmode exclusive
Classic mode icon.png Classic
Expert mode icon.png Expert
Master mode icon.png Master
AI TypeDreadnautilus AI
Damage55/110/165 (contact)
60100150 (Blood Shot)
Max Life7000/14000/21000
KB Resist100%
BannerDreadnautilus BannerDreadnautilus Banner(Desktop, Console and Mobile versions)
Immune toConfused
Coins2 GC5 GC
Projectiles created
Projectiles created
Projectiles created
  • Blood Tears
    Blood Tears
  • Blood Nautilus Shot
    Blood Nautilus Shot

The Dreadnautilus is a Hardmode enemy that can be spawned by fishing in water during a Blood Moon. When the bobber dips and the player attempts to reel in a fish, a Dreadnautilus or another enemy (Wandering Eye Fish, Zombie Merman, Blood Eel, or Hemogoblin Shark) has a chance to spawn within a few tiles of the bobber in place of a fish. The Dreadnautilus is rarer than the other four Blood Moon fishing enemies, spawning from only 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 requires 10 kills to be awarded completion of its Bestiary entry and corresponding banner, as opposed to the usual 50 kills.


The Dreadnautilus has the following attacks:[1]

  1. The Dreadnautilus faces away from the player and charges up for 1.5 seconds, then dashes directly towards the player. When it is close enough to the player, it will spin around them. The dash attack lasts 3 seconds, and the Dreadnautilus will stop dashing and spinning after 3 seconds have passed.
    • While in the charging phase, the Dreadnautilus can reflect projectiles on all difficulties. For the complete list, see list of reflected projectiles.
  2. The Dreadnautilus faces towards the player and charges up for 1.5 seconds before firing three rapid sprays of red blood projectiles at the player, recoiling after each burst.
    • It will not reflect projectiles during this charging phase.
  3. The Dreadnautilus 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 repeat said attacks in the following sequence: 2, 1, 2, 3, 2, 1, 2, 1, 2, 1, 3, 1, 2, 1.[3]


  • 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.


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. (Desktop, Console and Mobile versions)
Category: Slayer Slayer


  • 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.
  • 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 a 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.
  • The dash attack can be avoided relatively easily via a quick burst of movement to throw off its tracking. This can be done with wings, hooks, or a dash from the Shield of Cthulhu, Crystal Assassin armor, or another source.


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.
  • Similar to the Ice Golem, Sand Elemental, and Mothron, the Dreadnautilus is not a boss or mini-boss, even though 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. This is evidenced by its lack of a boss health bar, the fact that it drops a banner, not a trophy, and the fact that it does not drop a relic in Master Mode.
    • Leinfors went 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 cirri.
    • Nonetheless, Redigit has referred to the Dreadnautilus as a mini-boss.[7]
  • 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.[8]
  • 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.[9]
  • 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 1.4.4:
    • Charge attack has less tracking and a wider turning radius, making it easier to avoid.
    • Projectiles are now no longer blocked by tiles.
    • Projectiles are more lit up/visible at night.
  • 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. There may be inaccuracies, as the current Desktop version Desktop version is
  2. Information taken from the Desktop version Desktop source code, method AI() in Terraria.Projectile.cs. There may be inaccuracies, as the current Desktop version Desktop version is
  3. Information taken from the Desktop version Desktop source code, method AI_117_BloodNautilus() in Terraria.NPC.cs. There may be inaccuracies, as the current Desktop version Desktop version is
  4. Information taken from the Desktop version Desktop source code, method BloodNautilus_CallForHelp() in Terraria.NPC.cs. There may be inaccuracies, as the current Desktop version Desktop version is
  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. It’s not a boss though. It’s a miniboss July 4, 2023
  8. Terraria: Journey's End (0:50) June 10, 2019
  9. Duke Fishron and The Aquarian Horde! (archived from the original) April 1, 2014