Terramorphous the Invincible

Terramorphous the Invincible is a boss in Borderlands 2. It was conceived as a tougher follow-up to Crawmerax the Invincible found in the Secret Armory of General Knoxx add-on from the original Borderlands.

Terramorphous is an enormous unique thresher that is only accessible once the main story has been completed. Like other bosses, it can be fought multiple times and will drop different loot each time, including Legendary items.

Mission
Terramorphous appears in a mission named You. Will. Die. (Seriously.), a reference to the You. Will. Die. mission in which Crawmerax appears. The mission can be accepted from Tannis in Sanctuary upon completion of the main story in both Normal or True Vault Hunter Mode.

Location
Terramorphous can be found in Terramorphous Peak which is only accessible via Thousand Cuts. Upon entering Thousand Cuts, take a right and enter Slab Town. Down a small walkway is a cave with a mysterious stone barrier and an altar that requires four Eridium to proceed. Once the Eridium has been placed on the altar, the stone barriers will part and Terramorphous Peak can be accessed and Terramorphous can be fought.

Upon entering the peak, head up the pathway until a large hole in the ground is reached. Jump down the hole onto the grate. The grate will open and deposit the player onto a wide open cliff area. A large ornate bone horn can be found overlooking the lake where Terramorphous resides. Blowing into the horn will summon Terramorphous.

In the distance a large gate with a vault symbol will open. Terramorphous will appear from out of the cave and the battle will begin.

Combat
Terramorphous has numerous phases when encountered. He starts with four spike tentacles, but can also summon large rock throwing tentacles. The rocks can be easy to dodge but will inflict heavy area effect damage upon impact.

After this he summons Beam Tentacles which are very dangerous but can be avoided by hiding behind rocks. After Beam Tentacles, he becomes a Pyro Tresher and summons Pyro Tentacles. He is completely immune to fire damage while he is in this mode.

After this phase, he summons Masher Tentacles and starts bashing the ground which has a powerful knockback effect that will send players flying into air.

In his final form he becomes a Black Hole thresher and begins to pull players towards him. This can be avoided by hiding behind rocks again.

Terramorphous can also very easily knock players off the platform. This can occur in two ways. One, he can smash the ground around him. You can avoid being knocked off by closing in on Terramorphous. He will still damage you (hopefully not kill you), but at least you won't get knocked off. The other way is that he can sling his tentacles at you. The only way you can't be knocked off by this is by going back into the wall. He will hit you into that but he won't knock you off. You can be completely be unaffected by this (meaning you won't take damage & won't get knocked off) by crouching with perfect timing. Jumping won't help you avoid this dangerous attack.

Notable Loot
Terramorphous can drop multiple items exclusive to him:


 * Slayer of Terramorphous - Class mod
 * Hide of Terramorphous - Shield
 * Blood of Terramorphous - Artifact
 * Teeth of Terramorphous - Shotgun
 * Breath of Terramorphous - Grenade
 * Boatmurder, Cold Steel, C0al Train, Shadaloo Stylish, XXX - Custom Heads

Solo
You can easily solo him with any character by equipping The Bee and Conference Call Legendary shotgun. This combination does a lot of damage and can quickly kill him. Using a Conference Call that has a fire elemental effect works the best over any non-elemental or elemental Conference Call.

By taking advantage of rock formations, it is possible to quickly kill Terramorphous with The Bee and any weapon that fires a large number of bullets - weapon damage itself is of secondary importance given that The Bee's Amp damage often exceeds shot damage by a factor of 5 to 10 or more. Miss Moxxi's Heart Breaker and the Lascaux are two easily obtained weapons that work very well for this purpose; the Heart Breaker can fire 80-90 shot in under 3 seconds, while the Lascaux's ability to rapidly fire 13 round (26-shot) bursts while zoomed makes it a good option for players who don't have access to a high-level Heart Breaker.

While it is possible to solo Terramorphous without The Bee by using the rock formations and the lip of the doorway behind the rocks, it is a difficult and time-consuming process that requires a large time investment to learn how to avoid Terramorphous' attacks and the tentacles' abilities; it also has a relatively low success rate and, even if the player does succeed frequently, it requires a very large amount of time for each kill.

Exploits
Upon dropping into the plain you fight Terramorphous in, there is a rock formation hugging a wall behind and to the right of where the player is facing when dropping in. Standing on this rock will protect you from Terramorphous himself, with a spot with room for one person that will protect you from most tentacles as well.

Post-update Strategies
So far it can be confirmed that Zer0 can solo kill Terramorphous not employing either the Bee or Conference Call. This strategy works with any current update, and requires Captain Scarlett DLC. It is worth noting that the ammo required for this kill is above the normal allowance, so you need to either collect enough ammo during the battle (which is tricky and requires shooting down a lot of tentacles) or a much easier way to achieve it -- equip a relic before the battle with additional sniper ammo (I use LVL50 +46% to sniper ammo). During the battle you can switch it to a relic of your choice once your ammo is within the normal allowance. Current record stands at 140+ sniper rifle ammo only (no other shots fired). Some of these shots were spent on tentacles, so total amount to kill just Terramorphous itself is somewhat less, also depends on your scoring critical success rate. Throughout the battle, reduced cooldown relic (mine is -31% cooldown) is one of the best for this job. Killing the beast may still be quite tricky, as it is easy to be either killed or pushed away from the cliff during its powerful sweeping attack. It makes it way easier to exploit the map however. The best choice is to use the road leading up the closed gate. Most of its attack are easy to avoid, and once it gets closer, you can jump down hiding among the rocks, then climb back again.

Trivia

 * Terramorphous can be seen from the waterfall area during the BNK-3R boss fight.
 * Terramorphous was designed to be fought by four level 50 characters.
 * Randy Pitchford has stated that one Gearbox employee has figured out a build in which he was able to solo the battle while publically displaying the fight at the Gearbox Community Day.
 * After defeating Terramorphous, occasionally his tentacles may still spawn and attack you which can prove dangerous to players who are busy looting him.