Conjunctivius

"Some of the guards tell of throwing bodies down there to feed her. Perhaps she just wanted to play?"

Conjunctivius is a boss in Dead Cells, found in the Insufferable Crypt.

Conjunctivius is shackled to the walls by three chains. Four platforms are arranged around the room.

Damage of a single hit is capped at 15% of Conjunctivius' maximum health. The damage cap for her tentacles is 25%.

Primary Attacks
Body slam Magic bolts Aura of Laceration Rain of bolts
 * The attack is telegraphed by a red line along which the attack will travel so you can easily get out of the way or lay traps in its path.
 * This attack has the boss staying still for a decent time. So a good strategy is to bait the boss into a position where she can be easily hit, like on or near a platform or the ground.
 * A good tactic is to hug a wall and wait there until the telegraph starts. Lay down a wolf trap and roll into the wall to dodge the hit. Conjunctivius will be trapped allowing you to attack with any weapon you want.
 * Placing a turret as well can increase damage dealt.
 * Be aware that the boss can use Aura of Laceration in this position.
 * The magic bolts can be blocked or parried back to the boss with any shield. You can attempt to dodge them by rolling or running but this comes with the risk of walking in the path of another bolt.
 * Staying out of its range is easy as the aura is only slightly bigger than the boss itself. Use ranged weapons or AoE/DoT inflicting weapons/skills to deal damage.
 * This attack has the boss staying still for a decent time. So a good strategy is to bait the boss into a position where she can be easily hit, like on or near a platform or the ground.
 * Lay down a wolf trap on her position when the attack starts and she will be trapped allowing you to attack with any weapon you want after the aura dissapears.
 * Placing a turret as well can increase damage dealt.
 * The magic bolts can be blocked or parried back to the boss with any shield. You can attempt to dodge them by rolling or running but this comes with the risk of walking in the path of another bolt.

Tentacles
Piercing strike Area sweep
 * Tentacles move around above and underground, so use a trap or freezing to keep them in place. This tactic can stop the Area sweep attack.
 * Underground tentacles can be tracked by the dirt they scatter while moving, but a DoT effect can be applied to a tentacle which the icon will stay visible for after they are buried, betraying their position.
 * They have fronts and backs, so slapping them with the Assassin's Dagger or Vorpan is usually quite effective.
 * The melee mutation can help farther by slowing down the fast-moving tentacles. This is especially helpful for brutality build players.
 * This attack can be parried. If they are underground, you must move a little to the side and face where the tentacle will erupt to parry. It is difficult to time, but doable.
 * This attacks always comes from the side of the wall that is the furthest away from you.
 * This attack can be parried.
 * However, if they are not stunned (may happen when using the Punishment Shield), they will immediately submerge after the parry and then burst from the ground. A skilled player would make sure that the tentacles will stay in place before starting to attack.

Weapons/Items

 * Most crowd-control effects (freezing/slowing/etc.) will have very brief (if any) effect on the main body or the tentacles. But they are affected by bleed, poison and fire damage.
 * However, the Wolf Trap is an exception. As she is the first boss, she will be quite vulnerable to the Wolf Trap's stun effect, allowing weapons to deal massive damage to her easily and it negates her main advantage, which is her high mobility. You will have to stand close enough for her to ram into them, however.
 * The player can exploit her ram attack for this purpose. If enough damage is dealt to her, Tentacle phases will begin consecutively due to the drastic amount of health loss.
 * Since many attacks can be parried, a shield is useful to blunt attacks and deal damage.
 * The Bloodthirsty Shield can apply AoE bleeds to the main body and all tentacles, making it easier to apply damage-over-time.
 * The Rampart can be useful to deal with the tentacle phases, as its parries give you force fields to damage the tentacles without needing to roll-dodge.
 * The Cleaver is useful for tentacle phases, as you can lure them onto the grinder and apply consistent damage-over-time.
 * Items that apply poison are also quite effective.
 * Long-range melee weapons like whips and spears have some advantage, as well as weapons with fast successive swings.
 * The Valmont's Whip is especially recommended, as it does critical hits at the tip, meaning that the player can easily take advantage of it's range while still able to avoid the boss' attacks. Each critical hit can take off significant chunks of her health easily. However, it seriously struggles to take out tentacles alone.
 * Magic Missiles are also a very strong pick, allowing you to hit the boss nearly anywhere on the map, if you can get the shots pierce first target affix, the tentacles are much easier to defeat.
 * Oil, oil grenades, and torches perform well due to AoE DoTs.
 * She does not have a front or back, so Vorpan and Assassin's Dagger are not very effective. They can still be used against the tentacles, however.
 * Turrets are useful, but with a few exceptions, they are generally less effective due to Conjunctivius moving quickly out of their range. They can also distract to the boss and its tentacles from you while you deal damage undisturbed (enemies prioritize deployed turrets and Biters spawned from Swarm).
 * The Barnacle, although ineffective against tentacles and is practically unable to distract them, can easily hit the boss and chip it off if deployed correctly on one of the platforms. However, it may only be viable for users with tactical builds.
 * This is not a fast fight. You must be patient and careful until you learn the fight well enough.

Lore
A series of lore rooms scattered around the Toxic Sewers and Ancient Sewers explain how Conjunctivius came to be.

It begins with a nameless, faceless corpse in the Sewers, likely infected by the Malaise. The body is bloated and one of its arms has mutated into a tentacle. Green goo trails from the body towards a small hole in the wall."'The body is all bloated... One of his arms changed into a tentacle. It's as if the body had started to mutate! A viscous substance is oozing out of the body and across the floor... like a snail's trail.'"After this encounter, the Beheaded finds that same trail of green goo and an empty cocoon next to a bigger hole in the wall, made by an adolescent Conjunctivius ."'(...) This strange substance on the ground again. The trail leads to a sort of... giant cocoon. (...) The trail ends at this hole. And it's one hell of a big hole.'"Later, the Beheaded stumbles upon the trail of green goo close to a corpse. The trail leads to the remains of a huge cocoon and a gigantic hole, which was carved by the adult Conjunctivius as she escaped."'Still this trail on the ground. Whatever this thing is, it's pretty obvious that it... grew. Or evolved. Or mutated.'"The corpse doesn't seem infected and wears prisoner clothes, which may imply it's the prisoner who escaped from the Prisoners' Quarters. Why he is uninfected despite being killed by Conjunctivius is unclear. Finally, a message left by soldiers tells how difficult it was to chain Conjunctivius, likely an order of the King. This explains why Conjunctivius is imprisoned in the Insufferable Crypt when the Beheaded arrives." Make sure you don't miss your guard duty outside the MONSTER's room. It wasn't easy to chain up. Wouldn't like to have to do it all over again! "

Trivia

 * Prior to the v0.7, the Baguette Update, Conjunctivius was named The Watcher. In the game files, she is called Beholder.
 * Conjunctivius used to be named Conjonctivius.
 * Conjunctivius's name is a reference to conjunctivitis, an inflammation of the eye commonly known as pink eye..
 * When defeated, her eye will cycle through various colors before she explodes.
 * Conjuctivius makes an appearance at the end of the Dead Cells' animated release trailer, albeit with a different coloration and distorted proportions.
 * She is somehow still able to move around even without the chains.
 * The enemy derived from her is the Sewers' Tentacle. This enemy imitates all attacks used by her tentacles during the boss fight.