Aquatic Scourge

"A horror born of pollution and insatiable hunger..."

The Aquatic Scourge is a boss that can be fought in the Sulphurous Sea biome at any point in the game, but is intended to be fought during Hardmode. Being the hydrated and mutated version of the Desert Scourge, they possess similarities in their drops but significant differences in their behavior.

Spawn
The Aquatic Scourge spawns naturally, albeit rarely, in the Sulphurous Sea. It can be summoned manually by using the Seafood at any time.

Behavior
The Aquatic Scourge is an aerial worm-like enemy, with segments in total. Once spawned, the Aquatic Scourge will be passive, slowly following the player. It will become hostile and rapidly accelerate upon being hit by the player and dropping to 99% health or lower.

Once hostile, the Aquatic Scourge will follow the player with curve-like movements with a constant speed. As it travels, it will release many different projectiles along its path.

The Aquatic Scourge enrages outside the Ocean and Sulphurous Sea, greatly increasing its movement speed. The boss will only enrage once the player has left both biomes.

Attacks

 * Every seconds, the Aquatic Scourge vomits out several projectiles from its mouth in a circular spread. These projectiles include:
 * in an evenly-spaced ring which travel quickly in a straight line.
 * in random directions and speeds that linger in the air for 30 seconds.
 * The Aquatic Scourge randomly releases and homing  from its tooth-less and toothed body segments respectively.

In Expert Mode

 * Segments are increased from 31 to 36 and size increased by 10%.
 * Toothed body segments fire Sand Teeth more often.
 * Releases 7 more Sand Poison Clouds and 10 more Sand Blasts in the vomit attack.
 * Increased cloud spread, top speed, and acceleration as health lowers.
 * If gravity is reversed, such as when using a Gravitation Potion, the Aquatic Scourge will triple its base speed and vomit rate.

In Revengeance Mode

 * Segments are increased from 36 to 41 and size increased by 5%.
 * Moves faster and has a higher top speed.
 * Vomits more often and Sand Blasts resulting from the vomit travel faster.
 * Every 11 seconds, the Aquatic Scourge performs a circle around a certain point at its path for 2 seconds before charging the player.
 * While spinning, it fires 3 barrages of sand blasts at the player.
 * It can not vomit while performing this attack.

In Death Mode

 * Segments are increased from 41 to 51 and size increased by 5%.
 * Acceleration and top speed increase depending on the player's distance from it and as its health decreases.
 * Sand Blasts and Teeth travel even faster.
 * Fires a wider spread of 5 sand blasts while spinning.

During the Boss Rush

 * Does not have a passive nor an enrage state.
 * Vomits every 5 seconds instead of.
 * Sand Poison Clouds travel 25% farther.

Aftermath

 * Once defeated, the Sea King will begin selling Seafood.
 * Anthozoan Crabs, Baby Flak Crabs, and Belching Corals will begin to spawn in the Sulphurous Sea.
 * The second tier of the Acid Rain and all of its associated Content will become available.

Resistances

 * All segments take reduced damage from non-minion piercing projectiles in Expert Mode. Projectile damage is divided by the number of times it pierces. Infinite piercing deals 50% damage.
 * All segments reduce damage from grenade-type projectiles by 80%. A list of affected projectiles is below.


 * Additionally, all segments take:
 * 90% damage from the Hell Burst.
 * 75% damage from the Hydraulic Volt Crasher.
 * 50% damage from the SHPC's explosions and the Dormant Brimseeker.
 * 10% damage from the Brimstone Sword's explosion.
 * In addition, the pierce on the explosion is updated to 2 once it hits a segment.

Tips

 * This fight is very difficult to tank. Avoid the tooth projectiles and gas clouds at all costs and use weapons with ranged options if possible.
 * Avoid the head as much as possible, especially on Revengeance or Death Mode, as its high contact damage can kill the player extremely quickly.
 * Spawning the Aquatic Scourge when trying to fish in the Sulphurous Sea is a good idea, as it strongly reduces enemy spawn rate while it is alive. Due to the time-consuming nature of fishing or waiting for the Scourge to spawn, it is highly likely that it will spawn while the player is fishing.

Trivia

 * The theme heard during the Aquatic Scourge battle is Outcast of the Sulphurous Seas, which was composed by the artist DM DOKURO.
 * The theme is a remix of the Desert Scourge’s theme.
 * If the Calamity Music add-on mod is disabled, Boss 2 will play instead.
 * Because it is a more powerful version of the Desert Scourge, many of their drops are shared. The Aquatic Scourge's weapons are upgraded versions of the Desert Scourge's weapons, as well.
 * This boss and the Desert Scourge can both drop the Aero Stone and several fishing drops, making them the only two bosses to share a drop outside of crafting materials, potions, or fishing items.
 * The Aquatic Scourge's design was initially a redesign of the Desert Scourge made by Frous, a spriter for the mod.
 * With a passive state longer than that of Crabulon's (the Scourge will always remain passive unless attacked, Crabulon will wait a while before attacking) and it slowly following the player, then rapidly accelerating when attacked, it could be postulated that the Aquatic Scourge has some degree of intelligence or sapience and is simply curious about the player.
 * Similarly to Leviathan and Anahita, the Aquatic Scourge can be accidentally summoned in Pre-Hardmode, although the latter will not be immediately hostile.
 * The Aquatic Scourge was previously an alternative for The Twins because of its previous ability to drop Souls of Sight.