Lephantis

Lephantis (previously known as J-2000 Golem) is a massive Infested boss introduced in Update 10. It was originally going to replace J3-Golem but was moved to the new Orokin Derelict tileset instead. Lephantis is unique as a boss as its mission requires parts for an assassination key on the Derelict which requires parts only obtainable from other Derelict missions which require keys crafted from parts that can be obtained from containers and lockers of any mission.

Doing the boss solo is discouraged as it may be difficult for some players as the constant poison, electrical hazards and enemies can kill players who are not careful. Also, the boss has a very large health pool making him a giant bullet sponge. Players without good, ammo efficient gear will need a lot of time and ammo to kill him alone.

Appearance and Abilities
Lephantis is a massive three-headed creature with several limbs. Each head has a unique appearance as well as different abilities and can be identified by their own names. All three heads are connected to a large spherical body, which has three legs positioned like a tripod.

The "Infested Corpus" head resembles a severely mutated Corpus with a mouth taking up its entire face which has two tentacles on either side to cover it up when not attacking. It can spit poison grenades at great distances leaving behind poison clouds that deal very high damage and ignore shields. It can also release Infested Spawn Pods which will spawn multiple basic Infested units over-time until it is destroyed or expires on its own at which time it also leaves behind a cloud of poison.

The "Infested Grineer" head has a triangular jaw and wields a massive organic scythe-arm. It will either swing its scythe in a wide horizontal arc or bring it crashing down in an overhead strike. The scythe is capable of destroying obstacles in the arena as well as inflicting knockdowns with every hit.

The "Ancient Infested" head sports a long, stout jaw as well as the "halo crown" that normal Ancients have on their backs. It will spit an arc of Spore Bombs that explode a second after hitting the ground. While the bombs have a massive radius, they do not ignore shields, however, the massive damage and can kill any low level warframe in 1 hit.

Lephantis itself can use stomp shockwaves to knock back any nearby Tenno. Its heads can also inflict knock-downs by emerging from right beneath players. During the 2nd phase, the arena will have pools of electrified water as well.

Lephantis uses the exact same taunts as J3-Golem.

Stats
[1]per boss part, including the second phase of Lephantis.

[2]These parts have no armor.

Phase 1
During Phase 1, Lephantis will attack by poking its heads through the ground from below to take potshots at the Tenno. The fight starts with the Infested Corpus head, with the Ancient Infested head following soon after. The Infested Grineer head joins the fray about halfway through.

Each head is completely immune to damage except on their weakpoints, which are only revealed when they attack. The Corpus head's weakness is its mouth, the Ancient head its neck, and the Grineer head its mouth and neck.

Your primary goal should be to destroy the Corpus head as soon as possible, as it is the only one that can ignore shields as well as spawn Infested minions. Do not significantly damage the Ancient head yet. The best way to do so is to strafe around the outer edges of the arena and keeping your gun pointed at the Corpus head whenever it emerges. Whenever its mouth opens, blast it and then sprint as it will attack immediately afterwards.Be wary of the Ancient head's spore bombs, though they are of a much lesser threat. Ignore the Infested Spawn Pods as they will expire on their own given enough time and the Corpus head will keep spitting more out anyway. As long as you keep moving the attacks shouldn't directly hit you and the Infested spawns won't be able to catch up with you. Just be careful not to wander into the lingering poison clouds.

When the Corpus head is near death (assuming you didn't significantly damage the Ancient head), the Grineer head will join in. Thankfully, its attacks are relatively inaccurate and its biggest threat to you will be emerging from beneath you and knocking you down. At this point all three heads will be able to attack you at once, so you may want to be more aggressive and knock out the Corpus head as soon as possible to avoid being overwhelmed.

Once the Corpus head is down the rest of Phase 1 should be relatively easy. Destroy all of the remaining Spawn Pods as well as the Infested minions. Now focus on the Ancient head. Every time it spits an arc of bombs at you simply sprint towards the head to avoid the explosion (you will still get hit due to their massive range, but the damage is negligible long as you have decent shields). The Grineer head is generally too inaccurate to hit you with its scythe and can be out-ranged very easily, though it tends to emerge right next to or outright beneath you which can often knock you down. Simply keep your distance from the Grineer head and knock out the Ancient head.

Once the Ancient head has been taken out the Grineer head should be a walk in the park. Remember that it cannot hit you if you stay directly beneath it, so when it bursts up run straight towards it, stay as close to it as possible, and blast away at its "face" every time it swings. The mouth itself is also a weakspot, but you can only damages it when it opens which is when it attacks, so you have 2 weakspots to choose from. If you are below the head then shoot the face; if you are further away it might be easier to shoot the mouth rather than aim at the face from an uneasy angle.

Phase 2
Once all three heads have been fought off, you will be given a brief moment to pick up goods remaining on the arena before all three heads emerge at once and bring down the entire platform. Players will fall down into the ruins below, where the rest of Lephantis resides.

Phase 2 is essentially the same as Phase 1 except all three heads can attack in conjuction and the heads cannot retreat. The environment is darker and tinted red due to the nature of the arena which may cause trouble to those with difficulty dealing in such an environment. Again, you should focus your efforts on the Corpus head due to its lethality though you could also attack the Ancient head instead as it's an easier target to hit this time.

Standing directly in front of one head greatly helps, as it makes it difficult for the other two heads to attack you, but they will still try. The elevated platforms can be of great help as the Grineer head has trouble hitting people who stand on them as long as Lephantis is not right next to the platform. If Lephantis is close enough (as in so close it cannot move forward anymore), it can perform a higher side-slash to hit you off the platform, though the slash can be rolled under with good timing. Don't get too close to Lephantis or he will knock you down with his body slam. Avoid any electric pools and poison clouds as they can drain your health without you knowing until it's too late. Consider keeping some infested spawn pods alive as the spawned Infested can drop ammo and energy orbs. Try to focus on taking down the same head one at a time while avoiding the other two (though keep an eye on them so you can avoid their attacks).

Bring down the heads one at a time until you emerge victorious from the battle.

Bugs

 * Currently, there is a bug where on laggy matches, only the host will be able to deal damage to Lephantis with weapons. All abilities still work properly including Damage abilities, such as Antimatter Drop and CC abilities like Rhino Stomp, so you can still contribute to the fight.
 * If the host remains idle, all players disconnect apart from the host
 * Taunts currently use J-3 Golem's texts as well as its picture.
 * Banshee's Sonic Boom can displace the heads in the first phase which can result in them not showing up or becoming invisible.
 * If Saryn uses Miasma when Lephantis is low on health, it will start to disintegrate while it is still alive and if Lephantis does not die during that time, Lephantis will become invisible.

Trivia

 * Lephantis is the only boss to not directly drop a blueprint. Instead players get the Nekros components as a mission reward upon completion of the entire mission. Players will always get one component on each successful run though there is no guarantee the components will be different each time.
 * Underneath the Infested Grineer head there is the face of a person; it's unknown whose face it actually is. This is akin to Dark Sector's boss Mezner who also is fought in a large arena type area and whose face is distorted and stretched over the infested creature.
 * Golem Nav Coordinates can be found in lockers and crates throughout the mission allowing recuperation of some, if not all, of the coordinates used in crafting the assassination key.
 * Lephantis is always level 50.
 * Should you point your mouse over the central body during the second stage you will see an indicator of total health (percentage health of all the heads). This gives a good indicator of how much of the battle there is left to fight.
 * It is possible to ride Lephantis by jumping from the platforms or by using powers to get onto its back. However, it has a tendency to knock you off, dealing damage.
 * If you listen closely Lephantis' taunts sound like an edited version of Kril's.
 * Originally upon defeating the three heads in Phase 1 the ceiling would break causing the floor to crumble from the falling debris. This was changed in favor of Lephantis breaking the ground directly.
 * Lephantis is currently the largest boss in the game and also has the most health. It is also the first boss to have had its name changed.
 * If Molecular Prime is used in the first stage, the seperate heads will dissapear like normal primed enemies, but still be on Lephantis in the second stage.
 * Sometimes, when a primed head is killed in the second stage, a blinking ghost outline of it will remain.