Terraria Calamity mod boss list and guide

Terraria will always have a special place in my heart thanks to its whimsical atmosphere, pixel art style, and soundtrack that just hits differently. Even though I can spend hours playing vanilla Terraria, turning to mods like Calamity is inevitable.

Calamity, for all of you who don’t know, is a special mod that adds a ton of new bosses, biomes, structures, additional recipes to craft, more songs to vibe to, and a new way to level up. This mod is huge, providing weeks of extra fun. On top of all of this, it’s quite a challenge, even for Terraria veterans.

Here’s the full list of Terraria Calamity bosses and additional guidelines on preparing for combat and summoning bosses.

How to prepare for Terraria Calamity mod bosses

In Terraria, charging blindly into bosses is not the best idea. Instead, it’s best to grind up weapons, increase your armor, and collect the necessary reagents. On top of that, I recommend stocking up on consumables before you go toe to toe with the strongest creatures in Terraria.

It’s also worth building your own fighting platforms with more than enough space to kite the bosses and dodge their abilities. You can deposit all your goodies to Piggy Bank if you think there’s a chance you might fail. 

How to summon Terraria Calamity mod bosses

Bosses in Terraria rarely spawn on their own. Instead, you have to create summoning items for them to spawn. Summoning methods can vary from getting different items and throwing them into a body of water to simply finding a certain reagent and using it in a specific area. Each boss in Terraria and the Calamity mod has a unique way of summoning.

To summon stronger bosses, you first need to defeat the easier ones. That will change your map, allowing you to access the areas you didn’t have access to before. Remember, bosses spawn under certain conditions. For example, some can be spawned at night or in the jungle. 

Full list of Terraria Calamity mod bosses

Mini bosses 

• Giant Clam: Natural spawn
• Cyber Draedon: Summon by placing the Bloody Vein into a Lab Hologram Projector
• Clamitas: Spawn by using Eye of Desolation during the night
• Earth Elemental: Natural spawn
• Onyx Kinsman: Interact with the Onyx Excavator
• Aether Valkyrie: Use Torrential Tear while at Floating Islands
• Cragmaw Mire: Spawns after the Acid Rain event
• Armored Digger: Spawns after you defeat Plantera
• Great Sand Shark: Spawns after you kill 10 Sand Sharks during a Sandstorm (you have to defeat Plantera)
• Plaguebringer: Natural spawn after slaying Golem
• Colossal Squid: Natural spawn in the Abyss biome
• Reaper Shark: Natural spawn in the Abyss biome
• Eidolon Wyrm: Natural spawn in the Abyss biome
• Mauler: Natural spawn during Acid Rain
• Nuclear Terror: Natural spawn during Acid Rain

Pre-Hardmode bosses

• The Calamity: Spawns by using the Awakening lore item
• Goozma: Summon by placing 10 Overoaded Sludge onto King Slime during the Slime Rain (only when you activate Slime with Tar Gar)
• The Inventors: use Draedon Power Cell consumable on a Wulfrum Signal Transmitter (craftable item)
• Wulfrum Excavator: Hit Wulfrum Amplifier with any pickaxe. You have to have Ogscule in your bags.
• Desert Scourge: Summon it in the desert biome using the  Desert Medallion
• Crabulon: Use Decapodita Sprout when in a Glowing Mushroom biome
• Monstro: Place a Bloody Vein into an Anomaly 109
• Acidsighter: Summoned in the Sulphurous Sea during the night when you use Poisoned Sclera
• The Hive Mind: Summon it by using Teratoma or by defeating a Hive Tumor
• The Perforators: Get Bloody Worm Food or defeat Perforator Cyst in a Crimson biome
• The Slime God: Spawns upon you crafting and using Overloaded Sludge

Hardmode bosses

• Cumulomenace: Use Puffy Abomination at the height of Floating Islands.
• Cryogen: Go to a Snow biome and use Cryo Key
• Pyrogen: Throw Cryo Key into lava
• Aquatic Scourge: Natural spawn or by using Seafood
• Brimstone Elemental: Use Charred Idol in the Brimstone Crag
• Calamitas Clone: Use Eye of Desolation at night
• Serial Designation N: Use Disassembly Signal during the night
• The Forbidden Lantern: Use Lantern Shard
• The Derellect: Use Mechanical Worm when you have a Bloody Vein on you
• Polyphemalus: Use Fused Eye during the night
• Leviathan and Anahita: Defeat an ocean boss with Wakasagihime
• Astrum Aureus: Gather Famine Slime, Pestilent Slime, War Slime, and Death Slime 
• The Plaguebringer Goliath: Summon in the Underground Jungle by using Abombination    
• Ravager: Hit Ravager while it’s deactivated
• The Dragonfolly: Use Flare Gun and fire Exotic Pheromones during the day in a Desert biome
• Artificial Sentience System, AX-P03: Use Emergency Transfer Machine
• Astrum Deus: Use Astral Beacon (you need to have Titan Heart or Starcore in your bags)

Godseeker Mode bosses

• Profaned Guardians: Use Profaned Shard in the Hallow or the Underworld
• Providence, the Profaned Goddess: Use Profaned Shard in the Hallow or the Underworld (encounter changes depending on the summoned timing (night or day))
• Storm Weaver: Use Mechanical Weaver
• Ceaseless Void: Summon by using Rune of Kos in the Dungeon
• Signus, Envoy of the Devourer: Summoned by using Rune of Kos in the Underworld
• Polterghast: Use Necroplasmic Beacon in the Dungeon
• The Starborn Moth: Summon by using Celestial Geode in The Hallow (during day). Can also be summoned 
• Profusion, the Viral God: Get and use Oddest Mushroom in a Glowing Mushroom area
• The Devourer of Gods: Craft and use Cosmic Worm
• Horseslimes of the Goopocalypse: Hold Gooz Sayer’s Coin and interact with Apocalyptic Slime Statue
• Jungle Dragon, Yharon: Go to the Jungle biome and use  Jungle Dragon Egg
• The Wall of Bronze: Put Bloody Vein into the Ancient Console
• The Fabricational Quartet: Summoned by making a gateway from Rusted Pipes and putting Auric Quantum Cooling Cell onto it. Then, enter The Exosphere and choose which monster you want spawned first. 
• XP-00 Hypnos: Create The Codebreaker and an Auric Quantum Cooling Cell and interact with it. Place Bloody Vein into Draedon Power Cell.
• Yharim Worm: Place a worm into The Codebreaker or Altar of the Accursed.
• Supreme Calamitas: Interact with Altar of the Accursed
• XB-10 Losbaf: Make The Codebreaker and an Auric Quantum Cooling Cell and interact with them. Place Shadowspec Bar into Draedon Power Cell. 
• XC-39 Oizys: Place Brimstone Locus into the Codebreaker (you also need  Auric Quantum Cooling Cell).
• Goozma: Throw 10 Overloaded Sludge onto King Slime during the Slime Rain (only when you activate Slime with Tar Gar)
• Godseeker, Yharim: Natural spawn

Superbosses

• Adult Eidolon Wyrm: Go to the Abyss and wear Abyss Shell Fossil pet or get Chaos State debuff
• Vision of the Tyrant: Defeat Supreme Calamitas
• The Entropic God, Noxus: Get and use Genesis
• Esserwyrm: Natural spawn
• Reactive Guardian, Sodis: Throw Artificial Reactive Matter onto Aquatic Hypercomputer
• Exodygen: Use Eschaton