Dr. Eggman (formerly known as Dr. Robotnik) is a prolific inventor, a trait that has served him well since his very first appearance in the original Sonic the Hedgehog: it was a common feature in Sonic games to face the nefarious scientist as a boss at the end of every stage - equipped in one of his many war-machines.
So it is only fair we take recognition of his genius by including a list of his more prominent war-machines as they appeared in the Sonic games (note: for the sake of sanity we'll only be including official Sonic games in this list, as trying to add all of Robotnik/Eggman's war-machines from unofficial ROM-hacks or fan-games would be almost impossible to achieve).
Sonic the Hedgehog
Eggmobile (Wrecking Ball)
The first boss of the game and also the first of Robotnik's War-Machines that Sonic fights while being controlled by the player - it is a modified version of his famous Egg-Mobile, fitted with a very large wrecking ball that he swings at Sonic in an attempt to crush the hedgehog.
After taking some damage Robotnik ups the power of the Wrecking Ball, making it go faster, yet inevitably it ends up being destroyed and leaves an ash-covered Robotnik to make a hasty escape using his Egg-Mobile (which is still barely functional, despite the carnage).
Eggmobile (Fireball Weapon)
In the Marble Zone, Eggman rides his Eggmobile with a new weapon under it, which can spew fireballs from it.
Eggmobile (Spike Weapon)
The Eggmobile can use its spike to take out the ground with it.
Eggman awaits you in his Eggmobile, then Sonic must chase after him while avoiding the rising water and numerous traps.
Eggmobile (Mine Dropper)
The Eggmobile can drop spiked mines from above. Sonic can use the see-saws to attack Eggman, or hit Eggman with his own mines.
Sonic the Hedgehog 2
Eggman is protected by a barrier while a laser gun on the ceiling occasionally shoots laser beams at Sonic.
The Eggmoblile decorated with casino lights, and with two claws. Can drop red spiked balls from above
A car with a drill piloted by Eggman.
A driil-like machine piloted by Eggman. It behaves much the same way as the Car Boss, but when it reaches the end of the screen it burrows into the ground, which causes boulders and stalactites to fall from the ceiling. Only the stalactites can hurt Sonic.
Eight egg spheres that protect the Eggmobile. After they are gone, the Eggmobile can shoot a green laser beam at Sonic.
A flying tank-like mech piloted by Eggman. When it emerges from the lava, it shoots fireballs that leave a trail of fire when they hit the ground.
A submarine mech piloted by Eggman. After it submerges in the oily water, a needle like snake appears and attacks. Second, a gun rises from the water and shoots Sonic. Then the submarine emerges and stays afloat for a few seconds allowing Sonic to attack it.
The Eggmobile can collect chemical water and dump it on Sonic
A hammer is attached to the Eggmobile. Can pound on the totem poles, forcing them to shoot arrows. Sonic can use the arrows to jump and reach Eggman when they are wedged into walls.
A giant battle mech built in the likeness of Dr. Eggman. Walks towards Sonic for a little while, then jumps up and tries to ground-pound him. It can also try to punch Sonic with its huge spiked fists.
Sonic the Hedgehog 3
The first mech piloted by Eggman in the final level, Launch Base Zone. Can shoot balls at Sonic
The second mech piloted by Eggman in the final level, Lauch Base Zone. Can shoot two lasers at once.
The third and final mech piloted by Eggman in the final level, Launch Base Zone. Can grab Sonic and can slam him to the ground with tremendous force, forcing Sonic to lose his rings.
A blue mech piloted by Eggman. Can shoot two fireballs.
A freeze mobile piloted by Eggman. Can freeze Sonic, making him lose his rings or shield.
A gravity mobile piloted by Eggman. Can drop the green ball and then spin around it with electricity.
Sonic & Knuckles
A large green blimp-like mech. Drops bombs as it flies over the level.
A golem piloted by Eggman. As it moves, it shoots a laser from its eye.
Great Eggman Robo
A hanging mobile piloted by Eggman equiped with a flamethrower on top.
A lavaproof submarine piloted by Eggman. It shoots spiked mines from a cannon on the top of the vehicle. Fortunately, the mines can hit Eggman if Sonic avoids them.
A jet mobile piloted by Eggman that flies backwards while Sonic or Knuckles chase after it.
Sonic Adventure 2
Nega Wisp Armor
Sonic Lost World
The final boss of the game. At the end of the game, Eggman reveals that he only wanted to help Sonic stop the Deadly Six so he could use the power from their Energy Siphon to power his "ultimate weapon" and Sonic is forced to fight Eggman. Sonic must battle the Egg Emperor while running. As he runs across the Lava Mountain Zone, the Egg Emperor performs three attacks in the same order: first it shoots many green sparks from its hands that can be avoided by staying in the middle of the path; then it fires laser beams from its fingers that Sonic must jump over; finally it smashes its hands together to try to crush Sonic. Then the Egg Emperor will try to crush Sonic against the screen by slowly moving its body closer and closer, which gives him an opportunity to attack by jumping on one of the robot's feet. When the Egg Emperor's foot is hit, it stumbles, allowing Sonic to jump his way up an arm to hit the head of the robot. Then it will roll on the ground, and Sonic can hit it anywhere to deal damage. Sonic must do this three times to defeat the Egg Emperor. As the Egg Emperor takes some damage, it ups its attack: the green sparks will start to move from side to side, forcing Sonic to move with them to avoid being hit or pushed into the lava; the Egg Emperor will fire more laser beams than it did before and the beams are faster now; and it smashes its hands three times instead of just once.