Eidolon Hydrolyst

"The Ostrons believe the Hydrolyst is an omen of impending natural disaster. Stories describe a distinct, pungent aroma that precedes the arrival of this toxic beast."

The Hydrolyst is a titanic spectral Sentient creature. This mythical Eidolon is a rare sight on the Plains of Eidolon at night, appearing only when it is ritualistically summoned. It is large enough to wield the landing strut of an ancient spacecraft as a weapon, and its arcane energies create localized storm systems wherever it surfaces.

All Eidolons are remnants of a Sentient that was defeated in a battle against the Tenno during the Old War, whose remains now wander the plains perpetually searching for their lost components. These fragments are, however, still formidable creatures armed with powerful attacks and near-impenetrable defenses, and are hostile to both Tenno and Grineer alike.

Summoning
To summon the Eidolon Hydrolyst, the Tenno must capture an Eidolon Gantulyst and offer the acquired Radiant Eidolon Shards to the Eidolon shrine on the island of the bigger lake in the middle of the Plains.

Behavior
*Some information may not be completely correct.

Hydrolysts emerge from the lake on the Plains after being summoned by the altar. Their location is marked with a column of green light. They generally walk in one direction, even if the Tenno are nearby, though their attention can be drawn to specific locations by using Eidolon Lures found throughout the Plains at night.The Hydrolyst has many different attacks which do extremely high damage, and while most of those attacks are telegraphed, they remain quite hard to dodge, even with extensive use of the Operator's Void Mode.
 * Ultra Seeking Bullets: A sphere of light emitted from the Hydrolyst's back which splits into multiple homing projectiles. These are more accurate than the Teralyst's, and are harder to avoid.


 * Ground Stomp: Stomps the ground, sending out a ground shockwave that knockbacks back any Tenno in its path a great distance (100 meter radius).
 * Ground Smash: Smashes the ground, sending out a series of high-damaging, homing quakes to the Tenno's position. These homing quakes can stun the Tenno and are 25m high. Shortly afterwards, geysers of acid water erupt from the ground, creating bubbles of green energy above them that can be shot at with the Operator's amp. If left unchecked, these bubbles eventually rain down acid rain, turning the ground below into a swamp covering a large area and dealing heavy damage to anything in it.
 * Gun Swing: Swings its gun arm while firing it in a wide arc, each bullet creating a 2m wide explosion..
 * Summoning Scream: The Hydrolyst glows green and screeches into the air. This will summon and buff Vomvalysts around it.
 * Regenerating Scream: The Hydrolyst glows green and screeches. This will cause surrounding Vomvalysts (that are not affected by Summoning Scream) to link to the Hydrolyst and begin to regenerate its shield. Additionally, this will render it invulnerable to all damage until all linked Vomvalysts are destroyed.
 * Ultra Sentient Residue: The Hydrolyst will "bleed" teal blood on the ground after losing at least one of its Synovia, dealing a lot of damage over time to those standing on it.
 * Ultra Star Fall: Fires its gun into the sky, causing a rain of explosive, slightly homing projectiles on all targets nearby. The explosives may cause knockdown. This ability can deal damage through Limbo's Rift Plane and Frost's Snow Globe. Base area-of-effect spans 300m in radius.
 * EMP Pulses: The Hydrolyst periodically emits radial magnetic pulses that can drain the Tenno's energy if they come in contact with them. As the battle progresses, the pulses become more and more frequent.
 * Vomvalyst Bloom Summon:  Throughout the fight, the Hydrolyst summons Vomvalyst Blooms, purple portals that will periodically spawn buffed variants of the Eidolon Vomvalysts. The blooms can also link to nearby Vomvalysts, making them immune to damage. It can only be destroyed with Operator attacks.
 * Buffed Vomvalysts include a Red Glowing variation armed with an Opticor beam that is fired on a cone that deals immense damage to Operators and Warframes alike after aiming, and a Blue Glowing variation which links to near Vomvalysts and has gigantic amounts of Overshields.
 * Lightning: Throughout the fight, the Hydrolyst alters the weather around it, creating clouds of heavy rain and summoning high-damage lightning. Small ripples of green energy on the floor briefly indicate where the lightning strikes. It seems the lightning cannot hit airborne players.
 * Sentient Mines: The Hydrolyst will sometimes drop smaller green orbs on the ground that explode dealing [?] damage to the player once they enter its radius.
 * Energy Spike: The attack Hydrolyst uses upon the destruction of one of his limbs. This will emit five pulses of high damaging Magnetic damage. He will repeat this five times.

General
Dealing with the Hydrolyst is essentially the same as dealing with its smaller counterpart the Gantulyst, in that he also possesses 6 Synovia (one on each knee, one on each arm, and one behind each of its armpits, thus requiring the use of 3 charged lures if players wish to capture it.

Much like the Gantulyst, the Hydrolyst moves quite fast, forcing the Tenno to run after him at all times and making it harder to hit its weak points.

As powerful as they are, the majority of the Hydrolyst's attacks only affect players on the ground. Spending time airborne is an efficient alternative to the Operator's Void Mode to dodge the attacks.

Capturing an Eidolon Hydrolyst yields 2 Brilliant Eidolon Shards, 2 Radiant Eidolon Shards, 2 Riven Transmuters, one mod from the drop list and a large amount of sentient cores of all types. The Hydrolyst may also drop an Eidolon Hydrolyst Articula, which can be placed in the orbiter for decoration.

Successfully capturing the Teralyst, Gantulyst, and Hydrolyst in a single night yields a total of 2 Riven Transmuters, 2 Radiant Eidolon Shards, 3 Brilliant Eidolon Shards, 9 Eidolon Shards, 17 Flawless Sentient Cores, 15 Exceptional Sentient Cores and a large amount of Intact Sentient Cores.

Tips

 * The increasingly chaotic nature of the Hydrolyst's attacks, coupled with the giant's increased speed, makes attacking its weak points harder than ever, while enduring increased counts of hardly-avoidable damage. Extensive use of defensive abilities, such as Trinity's Blessing, Harrow's Covenant and more will vastly increase the squad's survivability. Alternatively, one player with Unairu's Void Shadow and Void Chrysalis can cloak nearby allies while also greatly shielding them from damage.
 * Bringing Squad Energy Restores is very much appreciated, as the Hydrolyst sometimes lets out pulses of magnetic energy that can drain most of the Tenno's energy with little warning (those are not the same pulses created by Energy Spike, as these are much deadlier and frequently instant kill)
 * The Granmu Prism is recommended for taking down this hulk, as the Shwaak Prism's fall off range isn't efficient enough to do significant damage as he moves around marginally faster than his counterparts, and is much larger. The Klebrik Scaffold can be used as a complement to dispatch the Vomvalysts with ease.
 * The near-constant and massive inflow of Vomvalysts in the latter stages of the fight gives a notable edge in battle to the Hydrolyst, as using his Summoning or Regenerating Scream will either vastly enhance the strength and diversity of their attacks, or grant the Vomvalysts a large amount of shields while they replenish the Hydrolyst's own shields. As such, it is imperative to kill as many Vomvalysts as possible to minimize this threat.
 * Taking an Oberon, using with you, instead of a Harrow greatly increases your effective efficiency as the Hydrolyst has many magnetic proc abilities that Oberon's Hallowed Ground ability can disrupt.  can also be cast on squadmates to boost their Radiation damage output, the Eidolons' weakness.


 * Volt 's Electric Shields can be deployed to enhance both the Operator and the Warframe's damage. Be warned, however, that the Hydrolyst moves much faster than its counterparts and can quickly get out of range, drastically limiting the shields' effectiveness if not deployed often enough.
 * Zephyr can virtually ignore all of the Hydrolyst's attacks while also being able to shoot down its weak points with greater accuracy. This can be achieved by casting Turbulence to deflect all incoming projectiles, then charging Tail Wind to hover above the ground, thus dodging ground hazards and getting a clear view of the Hydrolyst's weak points.