Eggrobo (Sonic Lost World)

"I'm sick of you getting in the way EVERY SINGLE TIME!"

- Dr. Eggman, Sonic Lost World

Lava Mountain final boss is the boss of Lava Mountain and the final boss of Sonic Lost World. It is a giant mech powered by the energy of Earth, which Dr. Eggman harnessed via the Extractor.

History
The mech was constructed by Dr. Eggman in the period before the Deadly Six rebelled against him in Sonic Lost World and was specifically designed to be powered by the energy harvested from the Extractor. Before Eggman could deploy this mech, however, he was driven off from his operations by the Deadly Six when they broke free.

To get to his mech again and as well stop the Deadly Six from destroying the Earth, Eggman teamed up with Sonic and Tails. When Eggman and Sonic arrived at Lava Mountain, however, he faked his own death so he could get to the Extractor and his mech without anyone knowing. While Sonic took care of the Deadly Six, Eggman used the energy the Extractor had collected to super-charge the mech.

When Sonic and Tails got to the Extractor to shut it down, Eggman ambushed them in his mech. After Eggman had explained how he survived when he saved Sonic, the doctor revealed his plans to conquer whatever that was left of the world from the Extractor's effects with the same energies it had harvested. However, Sonic did not intent to let Eggman go through with his plan and engaged Eggman in his mech. In the end, the mech was no match for Sonic and was utterly destroyed.

Wii U version
The beginning of the battle takes place in a narrow, straightforward platform aisle that Sonic the Hedgehog runs on after being fired from a cannon. The final boss will launch both of its hands to the player, and will shoot out a string of energy bullets in a straight line. After that, the final boss will fire two lasers and move them across the pathway. Once this has been done, the final boss will move both of its hands and have Sonic the Hedgehog inbetween them so he can crush the player, the player must double jump to dodge this attack. After taking substantial damage, the final boss will move its hands while firing energy bullets and the laser attacks will sweep across the pathway much faster. After enough attacks, the player has the opportunity to hit the final boss via Homing Attack on the mech's model parts until they reach to the mech's face. Once hit, the mech will fall on the ground and roll until it manages to pick itself up again. Sonic has a chance to homing attack the mech while it is rolling to deal additional damage.

Nintendo 3DS version
The battle begins with Sonic already running after Eggman's mech. During the battle, Eggman uses powers of the Laser, Burst, Drill, Lightning, Asteroid and Quake. Between every attack, the power of the mech will be shown and will increase as the mech loses health. In Easy mode, it will start from 1000, then go up to 8000, then finally 10000. In Hard Mode, it will start from 1000, but temporarily go up to 5000 for one attack, then go down to 1000, then 8000, then finally, 10000. Finally as the boss of Lava Mountain Extra, it will start at 5000, then 8000, 10000, and will go past its limits as it reaches a power of 100000. When the mech is at its final power level, when Sonic has a chance to free two Wisps and one extra Wisp by landing an extra hit on it. Do this twice, and Sonic will have freed six Wisps, each Wisp granting Sonic some sort of strange power. After six Wisps have been freed, Sonic will charge at Eggman and use a super-charged Homing Attack powered by energy collected from the mech, forcing the player to rapidly press in order for Sonic to overwhelm the mech's defences and blow it up. Unlike the Wii U version, Sonic can transform into Super Sonic, but he will de-transform for the final attack.

Trivia

 * The robot has many similarities to various creations made by Dr. Eggman:
 * It has a similar design to the Death Egg Robot from Sonic the Hedgehog 2 and Sonic Generations. The cape is also similar to the cape worn by Metal Robotnik from Sonic the Hedgehog: The Movie. The color scheme is also similar to Egg Dragoon from Sonic Unleashed and Sonic Generations.
 * The battle between the this boss and Sonic has some similarities to the Nega-Wisp Armor fight from the Wii version of Sonic Colors.
 * You have aim at the cockpit to deal actual damage to the final boss.
 * When Eggman is defeated, he is ejected from his mech and sent soaring into the distance before exploding into an Eggman-shaped firework when he is out of sight.
 * In order to do damage the player must chain multiple Homing Attacks together also similar to the Sand Scorpion from Sonic and the Secret Rings.
 * After the player chains the Homing Attacks they will have another chance to deal extra damage.
 * The boss shoots lasers at the player from it's two hands that get gradually faster as more damage is done.
 * Much like the Time Eater from Sonic Generations, the Nintendo 3DS version uses more attacks than the console version. Also, like the Time Eater, both versions differ slightly in appearance (the cape on the Nintendo 3DS version appears much smaller).
 * This boss is able to detach its arms, a similar ability which Time Eater owns as well.
 * Eggman refers to it as his mech or his ultimate weapon, though both are merely titles and not the mech's name.
 * The boss bears great resemblance to the classic design of Doctor Eggman.
 * Although he has only one part, after you've done enough damage, the green eye of the robot begin to glow in green and you can hear that Eggman is getting angry, alluding to a second part.
 * It also bears similarities to the Egg Robo, in the sense that it can fly/hover, shoots lasers, has a robotic face, and looks somewhat like the robot in question.
 * This is the fourth robot to have a resemblance to Eggman, the other three being the Death Egg Robot, the Egg Robo and Egg Bot.
 * It was actually called Egg Robo in the game files.