Terramorphous the Invincible

Terramorphous the Invincible is a boss in Borderlands 2. It is a thresher with a powerful knockback attack that sends the player character flying into the air. Terramorphous will have multiple stages during the fight.

Terramorphous was conceived as a tougher follow-up to Crawmerax the Invincible found in the Secret Armory of General Knoxx DLC from the original Borderlands. Terramorphous appears in a mission named You. Will. Die. (Seriously.), a reference to the You. Will. Die. mission in which Crawmerax appears. According to Gearbox, the boss can be fought multiple times and will drop different loot each time, including Legendary items. It requires four Eridium to be able to fight Terramorphous. However upon defeating Terramorphous he will drop several Eridium so running out shoudn't be much of an issue.

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.

Strategies
Terramorphous was designed to be a boss for four level 50 characters, but can be soloed easily by players with The Bee equipped.

His attacks include throwing rocks and spikes at you, hitting you with his tentacles (which include Masher and Fire), becoming a Black Hole Thresher, or shooting you with his Beam Tentacles, which are the most dangerous.

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.

There is a Vault Symbol right by the platform you fall onto right before fighting Terramorphous. If you look up after falling, at the platform you will see this symbol. It is questionable on the technique used to reach this symbol however most say you must be hit up by the tentacles.

Trivia

 * Terramorphous can be seen from the waterfall area during the BNK-3R boss fight.
 * If you look behind the totem used to summon Terramorphous you will see a large gate witha vault symbol in the distance. After you begin to summon him the gate will open and Terramorphous will appear from out of the cave.
 * Acess to Terramorphous is unlocked only AFTER killing The Warrior, in both normal or True Vault Hunter Mode (also referred to as Playthrough 2).
 * Terramorphous can drop multiple items exclusive to him: Slayer of Terramorphous (class mod), Hide of Terramorphous (shield), Blood of Terramorphous (artifact), Fire Teeth of Terramorphous (shotgun), and the Breath of Terramorphous (grenade).