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"Rusty Seas Update"
Release date April 15, 2020
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The (or update added several expansions to the Sulphurous Sea along with a few other items and balance changes. The update is also notable for the name change of the Bumblebirb into The Dragonfolly.





  • Toxic Bubbles from the Sulphurous Sea no longer appear while a boss is alive.

Aquatic Scourge

  • Now takes 99% less damage from the Brimstone Sword's projectiles and explosions.
  • No longer drops Souls of Sight.
  • Tier 2 Acid Rain is now forced 10 seconds after defeating Aquatic Scourge.

Astrum Aureus

Astrum Deus

  • Increased worms' resistances to the Aerial Bane from 80% to 90%.

Brimstone Elemental

  • Changed laser telegraph from dusts to a line.
  • No longer drops Souls of Fright.


  • Now charges twice after every set of fireballs and lasers fired in her second phase in Revengeance Mode.


The Destroyer

  • Reduced Frozen and Chilled time from frost lasers.
  • Decreased resistance to the Spent Fuel Container from 66.67% to 62%.
  • Now takes 90% less damage from the Brimstone Sword's projectiles and 99% less damage from its explosions.

The Dragonfolly

  • Red Lightning Aura no longer deals damage until fully materialized.

Duke Fishron

Lunatic Cultist

  • Now takes 25% less damage from the Resurrection Butterfly.

The Old Duke

  • Tooth Ball teeth now have less lifespan.
  • Sulphurous Sharkrons no longer deal damage until fully visible.
  • Updated resistances:

Profaned Guardians


Storm Weaver

Other NPCs

  • Charred Slimes now spawn after the Brimstone Elemental has been defeated instead of after Plantera has been defeated.
  • Flak Crabs can now only spawn underwater.
  • Nuclear Toads now spawn less frequently.
  • Town NPCs now have an icon above them when new items are available in shops. They can be turned off via configuration options.
  • The Abomination from the Fargo's Mutant Mod can now cancel the Acid Rain event and sells the consumable Caustic Tear after it has been defeated.
  • The Sea King now sells the consumable Caustic Tear after the Acid Rain is defeated.
  • Reduced the amount of kills to clear the first two tiers of the Acid Rain event from 180 kills to 90 in Tier 1 and 125 in Tier 2.
  • Nerfed Tier 1 Water Leech's damage from 30 / 51 to 20 / 34.


Balance and Reworks

Balance Changes


  • The Dance of Light now fires a flurry of light blades instead of white splitting flares, causing a flash of light to erupt after 300 hits. Buffed damage from 700 to 2077, critical strike chance from 4% to 24%, and mana cost from 9 to 6. Decreased velocity from 30 to 14.
  • Nerfed Draedon's Heart's passive damage boost from 10% to 5%. It now inherits the reworked effects of Laudanum and Stress Pills below:
    • Laudanum no longer grants stat boosts or immunity to the Horror debuff. It now causes Horror to last twice as long, but provide the player with several positive buffs instead of harming the player.
    • Stress Pills no longer grant damage boosts and nerfed defense boost from 8 to 4. It now makes hits during a boss fight only remove half the Adrenaline Meter instead of the full meter.

Tier Changes

Additional Changes