Eidolon Gantulyst

"Legends say the Gantulyst wields an enormous boulder for an arm and radiates powerful beams of Sentient energy. The Ostrons built a shrine in its honor hoping to gain its favor."

The Gantulyst is an enormous spectral Sentient creature that can be summoned on the Plains of Eidolon at night. Much larger than the more common Teralyst Eidolon, it has replaced its right arm with an elongated boulder, and its massive weight creates shockwaves with every step.

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
After Tenno capture the Eidolon Teralyst they must offer their Brilliant Eidolon Shards on the Eidolon shrine located on the Sentient fossil in the middle of Gara Toht Lake.

Behavior
Gantulysts emerge from the Gara Toht Lake on the Plains after being summoned by the altar. Their location is marked with a column of orange 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 Gantulyst has many different attacks and several do extremely high damage, and while most of those attacks are telegraphed, they may remain quite hard to dodge, even with extensive use of the Operator's Void Mode.
 * Seeking Sphere: A sphere of light emitted from the Gantulyst's back which slowly travels to its target while firing somewhat inaccurate seeking bullets. These are very slow, and the sphere can either be dodged or destroyed with the Operator's amp.
 * Summoning Scream: The Gantulyst glows green and screeches into the air. This will summon and buff Vomvalysts around it.
 * Gantulyst Shields:  After a Summoning Scream or a Regenerating Scream The Gantulyst deploys a large orange dome covering the area around it, which blocks enemy fire coming from outside the dome. The dome moves with the Gantulyst, who acts as its center, forcing Tenno to get much closer to the Eidolon in order to damage it. Additionally, the dome emits pulses of energy that sap the health of anything outside it in a wide radius (300m). For some reason, the lures are extremely vulnerable to those pulses.
 * Ground Stomp: Stomps the ground, sending out a ground shockwave that knockbacks back any Tenno in its path a great distance (100 meter radius).
 * Knockback Pulses: If Gantulyst Shields are active, Ground Stomp is followed by 4 shockwaves with very powerful knockback. It can be dodged by jumping over them.
 * Energy Pillars:  If Gantulyst Shields are not present, Ground Stomp is folowed by several pillars of light emerged from the ground, dealing heavy damage to anything coming in contact with them. Small patches of yellow smoke and teal-colored ground briefly indicate where the pillars will emerge.
 * 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.
 * Rock Swing: Swings its rock arm inflicting damage to the Tenno hit with it.
 * Laser Swing: Similar to the Teralyst's Gun Swing, the Gantulyst swings its gun arm while firing a continuous beam of light in a wide arc. The laser leaves behind a trail of fire, which explodes shortly after.
 * Regenerating Scream: The Gantulyst glows green and screeches. This will cause surrounding Vomvalysts (that are not affected by Summoning Scream) to link to the Gantulyst and begin to regenerate its shield. Additionally, this will render it invulnerable to all damage until all linked Vomvalysts are destroyed.
 * Sentient Residue: The Gantulyst 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.
 * Star Prism: Fires a prism into the sky, which then explodes into multiple lasers firing in all directions, dealing heavy damage.
 * Energy Spike: The attack Gantulyst 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 Gantulyst is essentially the same as dealing with the Teralyst, with a few key differences:
 * The Gantulyst possesses 6 Synovia, compared to the Teralyst's four, thus requiring the use of 3 charged lures if players wish to capture it. These are located on each of its knees, elbows, and the back of its "armpits".
 * The Gantulyst is much bigger, and moves much faster than its smaller counterpart: because of this, hitting its weak points becomes more challenging.

Players who have control over the lures should stay as close to the Gantulyst as possible, in the event that the latter deploys his Gantulyst Shields (the orange dome). Lures outside the dome will not link to the Gantulyst's broken limbs and seemingly take fatal damage from the pulses the dome emits.

Capturing an Eidolon Gantulyst reimburses the previously sacrificed Brilliant Eidolon Shard, and yields 3 Eidolon Shards, 1 Brilliant Eidolon Shard, 1 Radiant Eidolon Shard, one mod from the drop list and a generous amount of sentient cores of all types. The Gantulyst may also drop an Eidolon Gantulyst Articula, which can be placed in the orbiter for decoration. Capturing the Gantulyst is required to summon the Hydrolyst, as it is the only way to obtain the Radiant Eidolon Shard necessary for the summoning.

Summary

 * Preparation Phase: Damage an Eidolon Lure and hack it to take control of it. The Lure can then be charged by either letting it absorb a nearby Eidolon Vomvalyst's spectral form, or by picking up the energy orb they drop (indicated by a blue beacon) and passing it onto the Lure. Each lure needs the energy of three Vomvalysts to fully charge. It is recommended to have three lures under control by the end of the hunt.
 * Phase 1: The Eidolon Gantulyst's shield can only be damaged with damage; this can be done with the Operator's power. The Synovia weak points will be vulnerable once its shields have been depleted.
 * Phase 2: Take down Synovia; this will trigger an energy spike of 5 waves in a 65 meter radius and yield an Exceptional Sentient Core for each one destroyed.
 * With no charged Lure: The Teralyst will teleport away, regenerating 75% of its shield.
 * With at least 1 charged Lure: The Gantulyst will not teleport away, regenerating only half of its shield.
 * Phase 3: Once all Synovia have been destroyed, the Teralyst will call upon surrounding Vomvalysts to heal it. Destroy these with the Operator.
 * Phase 4: The Teralyst's entire body will finally be vulnerable to damage. At this point it can be defeated.
 * With 0-2 charged Lures (Killed): The Gantulyst will collapse to the ground, yielding only three Eidolon Shards and an Arcane Enhancement.
 * With 3 charged Lures (Capture): The Gantulyst will be absorbed and dissolved into the ground, the Lures tethered to it explode, yielding a generous amount of Sentient Cores, three Eidolon Shard a Brilliant Eidolon Shard and an Arcane Enhancement.

Tips

 * The Operator's Void Mode is the best way to avoid damage from all of the Gantulyst's area of effect attacks, as Void Mode renders the Operator immune to all forms of damage, while leaving the Warframe similarly invulnerable to attack while the Operator is out as long as they're not channeling an ability. Companions remain vulnerable however, so using Void Dash to escape attacks and exiting Transference to teleport your warframe, as well as your vulnerable companions away, might be a better solution.
 * The Eidolon Lures do not take damage from the Gantulyst's energy spike.
 * Remember to keep the Eidolon Vomvalyst count around the Gantulyst to a minimum, as they can be a threat if ignored and enables the boss to regenerate their shields via the Vomvalysts.
 * Due to the larger size of the Gantulyst, the Granmu Prism often becomes more viable than the Shwaak Prism which loses its ability to deal multiple counts of damage in one hit on the Gantulyst because of its relatively short range. The Klebrik Scaffold can be used as a complement to dispatch the Vomvalysts with ease.
 * It is recommended that players with Eidolon Lures following them should not be the main source of damage in the squad, as the lures seem to frequently drift in front of the player, blocking shots and preventing the player from damaging the Gantulyst.
 * The Gantulyst tends to spawn directly in front of the Eidolon Shrine after being summoned. The Tenno can use this to their advantage by finding nearby lures before the fight.
 * Using the mod Shattering Impact is an efficent way to destroy all of the Eidolon's armor. (32 hits recommended to preserve Radiation damage bonus)

Trivia

 * Eidolon in Greek literature are spirit like images of a living or dead person.

Bugs

 * Even with charged lures the Gantulyst may still teleport away.