Calamity: Double Trouble Challenge

Calamity is a mod famous for its wide array of bosses throughout its progression, so I wondered what it would be like if the player were to try to take on 2 of each boss at the same time.

In this page is the layout of the challenge, as well as any interesting observations caused when trying to spawn multiple copies of bosses at once.

Anyways, on we go!

[Overview]

Double Trouble is the name I have given to the challenge. It may already exist under a different name, I don't know, since this was initially intended to be a personal project.

Double Trouble means the player has to face two of the same boss at a time when planning to fight bosses. This will usually require something like Cheat Sheet to spawn in the 2nd boss, since most bosses can only have 1 copy exist under normal circumstances without some sort of outside spawner like EoW's shadow orbs.

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Rules:

The goal is to beat all bosses and to beat both of each when fighting them. Killing one and then losing to the other doesn't count as beating the boss properly since, otherwise, it's basically just a slightly harder than normal Calamity run which sorta spoils the point.

An additional rule, depending on how confident you feel, is allowing extra accessory slots to make up for the notes below. This isn't necessary for the run by any means but some people may want some sort of compensation for needing to deal twice as much damage and dodge twice as many attacks, as minor as an extra accessory may be.

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Notes:

There are three things to note about spawning 2 of any type of boss:
-The player effectively needs to deal twice as much damage to have been considered to have 'beaten' a boss
-A 2nd boss makes dodging generally harder, sometimes reaching a point where cheap hits may be taken due to more complex patterns not intending to have a 2nd boss present alongside them
-Certain boss patterns, particularly when spawning things such as minions or changing forms, may break

I will not be discussing vanilla bosses here since, for the most part, their AIs do not conflict. The only real things to note are Plantera's tendrils all attaching to 1 Plantera, and the same for Golem's fists.

[Pre-Hardmode]

By far the easiest part of the challenge. Most boss patterns are very simple at this point due to how early-on things are.

Desert Scourge

Summary:
Desert Scourge's difficulty generally depends on if the player has a piercing weapon or not, which is the same for if multiple are present. Aside from the Revengeance spike projectiles the fight remains mostly the same

Difficulty Increase:
Low

Notes:
-Staying on a ledge just out of reach of the Scourges' basic burrowing is effective
-Piercing projectiles are, as expected, extremely powerful here

Weirdness:
None

Crabulon

Summary:
Another boss with low mobility, making the main threat here the amount of spores that two Crabulons can amass together. They aren't too mobile, so keeping track of them isn't too hard

Difficulty Increase:
Low

Notes:
-Making a platform out of reach of either of them is, as ever, effective
-Piercing weapons are very helpful for clearing out the spore projectiles they summon

Weirdness:
None

Hive Mind

Summary:
Phase 1 Hive Mind is as to be expected, with two bosses present. However, Phase 2 is actually basically the same as a normal Hive Mind fight

Difficulty Increase:
Low

Notes:
-Piercing, as usual, is helpful for Hive Mind's minions
-Defeat both Phase 1's as soon as possible, since some weirdness makes Phase 2 basically identical to a normal Phase 2 Hive Mind fight

Weirdness:
If a Phase 2 Hive Mind is active killing another Phase 1 does not spawn another Phase 2, meaning that the player would only have to fight one Phase 2 Hive Mind in this fight

Perforators

Summary:
Perforators do not have anything too exceptional to add; the two hives generally follow the same movement patterns and summon worms as normal. It's basically just an extended Perforators fight

Difficulty Increase:
Low

Notes:
-Piercing, as expected, is still useful for the multitude of worms summoned
-Trying to weaken the hives individually may be recommended, limiting the number of worms active at any time

Weirdness:
None

Slime God

Summary:
The fight is mostly the same as before, however the 6v1 scenario makes the fight still quite tricky due to how outnumbered the player is

Difficulty Increase:
Medium

Notes:
-Piercing weapons, as ever, are recommended for being able to deal with the large slimes and their minions faster
-A large arena is recommended to compensate for the increased quantity of mines spawned by the boss

Weirdness:
-Slime God Cores can occupy each others' slimes
-Both Slime God Cores can occupy the same slime at the same time

[Hardmode]

Now we're beginning to reach bosses that usually utilise more projectiles, but typically still have simple enough patterns that fighting two of them is still manageable

However, with more complex AI comes more room for bugs, so there's likely going to be a few more extra notes than normal

Cryogen

Summary:
Cryogen is mostly the same, but as before the increased quantity of projectiles makes things a little awkward. Fortunately it's not as bad as it looks, especially if the player has a long arena.

Difficulty Increase:
Low

Notes:
-Warmth Potion's only proper use is in this fight so you might as well use it
-Most normal Cryogen strategies apply here
-It is very easy to get the Cryogens to synchronise in the phases where they fly overhead, generally making dodging a little easier

Weirdness:
None

Aquatic Scourge

Summary:
It is, fortunately, easy to get the Scourges to overlap in this fight due to their mostly-predictable movement patterns of just following the player. However, as it is a boss that uses lots of projectiles and mines, there is opportunity for problems to arise

Difficulty Increase:
Medium

Notes:
-Piercing weapons work great here, since they can not only hit multiple segments at once but also both worms at once; significantly speeding up the fight
-A large arena is recommended once again due to the quantity of projectiles spawned and both Scourges' abilities to summon mines

Weirdness:
None

Brimstone Elemental

Summary:
This fight unfortunately becomes very hectic very quickly since, through the teleporting and AI changes, the Elementals quickly desync... which becomes a massive problem when they use the brimrose/Phase 3 attack too often

Difficulty Increase:
High

Notes:
-Prepare to be hit at least a few times during this fight, as the brimrose attacks do not tend to sync very well together and often fill the screen with projectiles very rapidly
-Focus primarily on defeating one of them before the other. This both means one can be removed from the fight to simply leave a fairly-regular Brimstone Elemental fight, and means only one of them will begin using the brimrose attack more frequently as opposed to both at once

Weirdness:
None

Calamitas

Summary:
Calamitas becomes significantly more of a challenge this time around, but moreso for just being hard to kill than actual new abilities. Her brothers boost both their defences at the same time and, with the amount of spawns in this fight, it's a race against the clock.

Difficulty Increase:
Medium

Notes:
-It is recommended to fight her Post-Plantera so the player can upgrade their gear to enhance their damage output and defences
-A hard-time limit is in effect during this boss, so defeating both in that time will likely require high DPS builds
-Reaver Armour's magic set bonus when combined with an Inferno Fork can decimate large chunks of both Calamitas' heal bars per hit, as discovered during an initial attempt

Weirdness:
Both Calamitas-es will become near-invulnerable when any brother is active, regardless of whose it is

Astrum Aureus

Summary:
Aureus isn't actually too much harder than normal here, given the player plays cautiously. Aureus' soft-time limit isn't too much of an issue if the player makes the proper preparations.

Difficulty Increase:
Low

Notes:
-Making an arena out of platforms that is too tall for Aureus to jump up significantly reduces the threat Aureus poses
--Platforms are important since Aureus just... seems to automatically fall through them even after a teleport
-Having a long platform to run along can help since it can cause the Astral Flame Crystals to lose their homing abilities before getting too close to the player

Weirdness:
None

Anahita and Leviathan

Summary:
This fight is mostly similar in concept to how it normally is, however the fact the player is likely going to be dealing with 2 Leviathans for a while makes it quite problematic. Somehow the phase transitions work as intended, even when spawning Leviathan in.

Difficulty Increase:
Medium

Notes:
-It is recommended the player tries to focus on killing one duo first to remove them from the fight. Phase transitions work as normal so careful damage can mean the player never has to fight double Leviathan and thus has much more dodging room
-Homing projectiles aren't really recommended for dealing with the Leviathans as they'll often just target the minions they spawn instead. Normally this isn't too bad but with two Leviathans active it can become a nuisance.
--Homing also makes it generally harder to focus targets when grouped-up, which relates to prior issues

Weirdness:
None

Plaguebringer Goliath

Summary:
The fight itself remains mostly the same in terms of events, however the presence of a 2nd Plaguebringer makes the charges especially problematic. Aside from the charges, however, the fight is manageable

Difficulty Increase:
Medium

Notes:
-If both Plaguebringers decide to charge you from different sides there's a very high chance you're just taking damage
-Focusing a single Plaguebringer may be recommended so both do not get access to the Plague Nuke Barrage at the same time

Weirdness:
None

Ravager

Summary:
Ravager is fortunately not very mobile in Phase 1 and has predictable movements in Phase 2, so it is one of those few bosses that overlaps during the fight and thus is generally a lot easier to dodge than it otherwise could have been

Difficulty Increase:
Low

Notes:
-Piercing is highly recommended once again since there's now a total of 10 body parts to kill among both Ravagers

Weirdness:
As with Golem all body parts among both Ravagers must be defeated in order to make them both enter Phase 2

Astrum Deus

Summary:
The fight, for the most part, is the same. Phase 1 is basically a slightly tougher Phase 2 and Phase 2 is once again only a little harder should the player be careful about what Astrum Deus they attack. The Astrum Deus heads produced during phase transitions (Mainly due to how the phase transitions break with more than 1 Deus) are mostly harmless
Also, due to the fact that all Deuses run away when one is killed, defeating only 1 will count as defeating the boss.

Difficulty Increase:
Low

Notes:
-Focus on only getting one of the Astrum Deuses down to half health. The fight actually becomes harder should the player bring both to Phase 2 at no benefit to the player
-When a single Phase 2 Astrum Deus is killed all Astrum Deuses will run away, including any still in Phase 1

Weirdness:
When Phase 2 begins whichever Phase 1 worm is still active will become just a head
Bringing both to Phase 2 creates 2 small worms and 2 heads.

[Post-Moon Lord]

By far the hardest part of the challenge, with bosses now having complex AI and a large variety of projectiles at their disposal.

Expect quite a few losses, even in lower difficulties.

Profaned Guardians

Summary:
The Guardians actually act basically the same as normal in this fight, with the main Guardians actually overlapping and synchronising if spawned in the same place. Other than the increased health there isn't very much to note here at all

Difficulty Increase:
Low

Notes:
-Piercing weapons help make quick work of the lesser guardians
-Spawning the main Guardians at the same time via autopause will keep them overlapping throughout the entire fight

Weirdness:
The main Guardians will only enter Phase 2 when ALL guardians are defeated, regardless of whose they were

Dragonfolly

Summary:
The Dragonfolly is normally a fast and aggressive boss with high contact damage, so imagine trying to have to deal with two at once. They do not synchronise at all and with two active the player is basically always getting charged at or rushed down, making the fight very hectic.

Difficulty Increase:
High

Notes:
-Most normal Dragonfolly strategies should work here, though do expect to be hit a few times
-Leaving this fight until later is still an option if the player is struggling, since there isn't anything immediately necessary dropped by the Folly.

Weirdness:
None

Providence

Summary:
This fight is, without a doubt, the hardest Double Trouble boss thus far and debatably the 2nd hardest one in the entire challenge. Even spawning them in the same place to keep them somewhat-synchronised isn't an instant-win due to how the fight works.
The Deathray and Crystal attacks are more annoying than usual as they can trap the player more easily, though this mainly comes from the Deathrays when the Providences aren't synced anymore
The Cocoon Star projectiles will either flood the screen from multiple angles or overlap and deal 300 damage instead, or some weird middle-ground that, whatever happens, makes the attack extremely dangerous whenever it is used.
Additionally, the Healing Guardians will heal both Providences at once and, since both can summon their own individually, that's basically 4x the normal healing they'd be able to accomplish; making the fight take even longer which then in turn allows Providence to use more Cocoon Stars.
The only saving grace to this fight is that if spawned in the same place the Providences will take a while to drift apart and desynchronise, giving the player a very mild mercy window.

Difficulty Increase:
Extreme

Notes:
-Saving Adrenaline and Rage for the Healing Guardians is recommended, as they can quickly undo much of the player's progress
-The player may want to consider spawning each Providences' Guardians separately to minimise the distractions they can cause when dodging the Providences' own attacks.
-Blood Pact, as well as any other health-boosters, are strongly recommended to make the Cocoon Star attacks to give the player the max chance of survival

Weirdness:
The Healing Guardians can heal both Providences, not just the one that summoned them

Polterghast

Summary:
Polterghast... just doesn't work. Due to what I can only assume is the aggression system summoning both causes them to take very, VERY wide turns or simply be dragged away from the Dungeon for some reason. They are too unstable to actually fight and will usually despawn after 1 or 2 attacks.
Even if one leaves the damage remains as the other's movements remain unusual and thus the 2nd will still also very likely be dragged away from the Dungeon and despawn

Difficulty Increase:
N/A

Notes:
-Doesn't work, have to fight it normally I'm afraid

Weirdness:
Spawning 2 of them messes with something and they begin drifting away until they despawn. One despawning does not fix the issue.
All tendrils attach to only 1... but that's not as pressing of an issue honestly.

Signus

Summary:
Starting with the most boring of the three in this challenge, Signus basically does not change and acts entirely as expected. The only real threat is that there is now a 2nd Signus

Difficulty Increase:
Low

Notes:
-Normal Signus strategies probably work here
-While they will desync fast a large enough arena will offset this issue

Weirdness:
None

Ceaseless Void

Summary:
The Voids will generally overlap due to their simple movement patterns, so the main issue comes from the spawns.
Both Voids become invulnerable when Dark Energies are spawned, and it is possible though awkward to get both to summon a cluster at the same time. Generally this is just an extended Void fight and nothing too much more complex.
There is one thing to note, however, about Void's gravity ability. Due to both overlapping the effect scales; potentially flinging the player across the arena. This is mainly an issue for the initial DoG fights since it can lead to Ceaseless Void despawning and ending the fight prematurely, but in the Dungeon's confined walls this is unlikely.

Difficulty Increase:
Medium

Notes:
-Piercing makes quick work of the Dark Energies as normal
-Most general Ceaseless Void strategies work here as well, since the fight moreso just extends as opposed to becoming actually harder

Weirdness:
Both Voids become invulnerable when either summons Dark Energies

Storm Weaver

Summary:
The most... interesting of the Sentinels. Due to Weaver's mechanic for the Phase 2 transition the 2nd Weaver (the one not transitioning) will become a head. While Phase 2 Weaver acts normal the head of the Phase 1 Weaver that will likely still exist is the main issue.
Weaver's head only takes 1 damage, so killing one Weaver means the player has to slowly chip away at the 2nd to transition it Dungeon Guardian style
Thus this fight is actually a puzzle; the player has to calculate how low they can get each Weaver before either transitions, making the process of killing the surviving head a lot easier. A high-health Weaver head is basically a forfeit since it'd take so long to kill that restarting the fight is far quicker

Difficulty Increase:
High

Notes:
-Bringing a spare low-damage weapon can help in chipping away at both Phase 1 Weavers to ensure they're both as low as possible before allowing either to transition
-Killing the Phase 2 Weaver, when spawned, is recommended as it lets the player focus on only the remaining head which, since it only takes 1 damage, may be desired

Weirdness:
Phase transition removes the body of the Phase 1 Weaver; leaving a Phase 2 Weaver and a Phase 1 Weaver's head active. Killing the active Phase 1 head continues the 2nd's Phase 2 as normal.

The Old Duke

Summary:
The 2nd Old Duke mainly just forces the player to play more defensively, as simply dashing out of the way of a charge won't work if they charge at different times.
Additionally, the whirlpools they spawn will be more numerous around the arena due to there being 2 Old Dukes spawning them separately, hindering player movements even further

Difficulty Increase:
High

Notes:
-A large arena is highly recommended to give the player plenty of room to flee the Old Dukes if needed, and allows the player to generally keep away from many of their projectile summons
-Since the Old Dukes will dash based on player movements, it's generally best to simply try to move away from them as opposed to past them, as it is likely that even if the first Duke misses the 2nd may hit. This is especially true for dashes of any sort

Weirdness:
None

Devourer of Gods

Summary:
The Devourer is probably the hardest boss in this challenge, even moreso than Providence or any bosses that come after, depending on how the player decides to fight them. Being a duo of highly-aggressive worm bosses gives the player little downtime and hinders player movement significantly.
Certain phases have their own issues to cover, so I'll split them up below:

Phase 1:
Moreso just a test-run to get the player use to having two highly-aggressive worms to dodge. Both worms have all their segments and act as normal, though note that Revengeance's Cosmic Guardians will probably break and spawn as just heads due to the spawn limits.
There is a risk of the Devourers also losing tail segments here if too many Guardians spawn, though this isn't guaranteed
The lasers in this phase aren't too problematic since it's moreso just that they're numerous.

Phase 1.5:
As mentioned in the Ceaseless Void chapter the stacked Voids can fling the player with their gravity abilities, potentially despawning them both and ending the fight.
The Weaver puzzle also returns during this fight, with the main issue being that if the player doesn't at least leave the 2nd on very low health it will likely survive until DoG's 2nd phase triggers and cause other problems
Signus remains a nonissue compared to the other points

Phase 2:
Note: Now, only 1 Phase 2 DoG spawns after the prior phases, but I took it upon myself to fight both by manually spawning the other. I didn't think to do this with Hive Mind in the initial attempt but felt it was only deserving that I fought both Phase 2 DoGs.
This was a horrible mistake.
Both DoGs remain as aggressive and still continue dealing massive damage, so both being larger and tankier just makes them even more troublesome to fight
The 2nd DoG will also spawn half-incomplete due to the spawn limit, meaning the player will have to attack that DoG's head for significant damage
The duo do not both go invisible during the laser walls, though even if both decide to use laser walls it isn't a grace period. If only one uses it the other DoG will continue pursuing the player and potentially force damage, but if both use it the laser walls aren't synchronised and may actively force damage if they spawn poorly.
The Cosmic Guardians will still spawn, only spawning in as heads, which can affect both the larger DoGs as well. So far I've not seen the other lose its tail, but I cannot confirm this is impossible.
Fighting both Phase 2 DoGs is a test of not just skill, but luck. Armageddon in this fight is basically impossible and Death Mode is also basically impossible as well due to how much RNG needs to go the player's way for a successful run.
Good Luck

Difficulty Increase:
Extreme

Notes:
-Piercing and AoE weapons are pretty good, I guess?
-Good Luck.

Weirdness:
DoG spawning limits cut off part of at least one DoG
Cosmic Guardians will also be bugged due to spawn limits
Both can teleport through the same portal if one chooses to spawn a portal. However upon testing this doesn't always seem to happen

Jungle Dragon, Yharon

Summary:
As dumb as it sounds, Yharon is actually a breath of fresh air after the DoG battle. Spawning them both at the same time will cause their attacks and movements to be near-perfectly synced until around 70% health I've noticed, where the phase transitions will desync them.
Like the Old Duke playing defensively is a good idea since fighting 2 Yharon's head-on is a recipe for disaster, even if they decide to remain relatively synced for a while.
One thing to note is that, upon taking either down to 10% for the first time, the first will despawn and the 2nd, once taken to 10%, will enter Phase 2 even if spawned at the same time and taken down to 10% at basically the same time. Now you could use that to cheat and only fight one Phase 2 Yharon but I decided to re-fight it with 2 Phase 2 Yharons and it's... still entirely manageable actually.

Difficulty Increase:
Medium

Notes:
-Mainly just play defensively and keep away from the duo as best as you can. Fighting them head-on is near-certain death so play cautiously and minimise any risks and you should be alright.
-If you consider the 'Phase 2' issue above to be cheesy you can always Save & Quit to despawn the other Yharon and then truly get to fight both Phase 2s. This may also be an option if you're that desperate to use Darksun equipment.
-Spawn them both in the same place, otherwise the border Infernadoes will cut off additional room in the arena.

Weirdness:
The 2nd Yharon will always enter Phase 2, no matter how little time passes after the 1st is taken to 10%

Supreme Calamitas

Summary:
Supreme Calamitas, being a bullet-hell boss, just mainly gains more projectiles. I shall discuss things in-order to keep things simple:

Supreme Calamitas:
The Supreme Calamitas seem to follow the same attack pattern, overlapping and synchronising. This means that, aside from the exploding fireballs, not too much changes for the parts that involve direct conflict with SCal. However, causing one to enter a phase transition and not the other will desync them. There are periods they seem to resync but these do not last.
The initial bullet-hells are fundamentally the same, though they spawn more fireballs. For some reason many of them follow similar paths to each other. If desynced so only 1 prepares a bullet-hell the other SCal remains vulnerable.
As soon as one SCal reaches 1% all Brimstone Monsters and projectiles despawn

Minions:
In the initial Sepulcher summon two Sepulchers are spawned, as well as 2 sets of Brimstone Hearts. However, they overlap with each other and thus this may be hard to spot. In the 8% Sepulcher summon both SCals become invulnerable, even if only one set has currently spawned.
When the brothers are spawned both SCals become invulnerable. Both can spawn brothers individually, as expected, however.
Brimstone Monsters spawn as normal

Difficulty Increase:
Extreme

Notes:
-The bullet-hells should not be triggered at the same time if possible. The sheer number of projectiles lags the game and basically forces the player will be hit at least once which, considering SCal's damage output, means even a single slip-up could end the fight

Weirdness:
Both SCals become invulnerable whenever one decides to spawn Sepulchers or her brothers.
You will receive the "I am free" message, regardless of how many times you've lost to SCal, when both are defeated

[Final Notes]

And that was a small page/guide thing on any notes you should know about should you decide to try and fight two or more of the same Calamity boss at once.

Now, I know I mentioned about spawning bosses on the same frame via autopause for bosses like Yharon, SCal and Providence, and by that I generally mean just using something like Cheat Sheet to summon both at once. Not a necessity, though.


I know this is a dumb page for a dumb challenge but that's... sorta what I do to be honest. I also figured since I completed it very recently what better a time to show my discoveries than when they're mostly fresh in my head.

I did this challenge alongside a fire-weapon-only challenge, making it harder on myself, and I still don't know why, so there are probably strategies out there that make certain fights here easier that I don't know about yet.


Anyways, hope you enjoyed my ramblings
See ya next time :P

(Also if you're wondering this is a guide thumbnail; a dumb meme I came up with due to the double Yharon fight's jank. I am sorry to expose your eyes to this mildly-fried abomination.)

[BIG MONKEY]

i can imagine adult eidilon (idk how to spell it) worm being extra fun when theres two of them

[BobaPlaysGames]

I know, and you can manually spawn a second trio of mechs(using HERO's Mod or Cheat Sheet) along with the second Draedon

[Okami Tomato]

y'know, this was made pre-Draedon, so maybe I'll have to update it with the mechs :)

(Tbh 2 Draedons might only spawn 1 trio of mechs still, but instead just mess up phase transitions)

[BobaPlaysGames]

Well there is one thing, do NOT spawn double Exo Mechs. Not saying I did that, but due to the already chaotic nature of the fight, I can't imagine what it would be like when fighting 8 bosses in the same vain.

[GDXpopdrop]

this is actually a real guide and not a troll good work

[Okami Tomato]

Oh! Wait I think actually the Hungries also only attach to the wall so the 2nd WoF is easier than the first

[Okami Tomato]

Double WoF is slightly broken as only the first wall spawned gets the... uhh... 'wall', the other becomes floating eyes and a mouth

Fortunately, aside from that, the fight works fine

[Are you sure?]

imagine wall of flesh:
double hungry bois
double lazor

[BrainDeadBoi2]

wow, this was something i thought of doing but i guess i got beat to it!

[BORB]

like how u can see every boss has its own guide and then
u see DoG... my mans wrote a F U C C I N G essay