The checkered wrecking ball-wielding Egg Mobile is the first boss in the original 16-bit version of Sonic the Hedgehog. The player fights it at the Green Hill Zone Act 3, where it is piloted by Dr. Robotnik and equipped with a massive, checker-board pattern wrecking ball that hangs suspended from its underside by a chain, swinging back and forth. Usually, the player only has to hop on the two floating platforms on the battle arena and hit the Egg Mobile eight times in order to defeat this boss. While it is unnamed in most appearances, the Japan-exclusive Sonic Advance Hisshō Perfect Guide dubbed it the Egg Mobile-H, with Egg Mobile Hammer Ball-shiyou (エッグモービル・ハンマーボール仕様 Eggumōbiru Hanmābōru-shiyō?) written under it in Japanese.
For simple equipped add-on, this version of the Egg Mobile is by far Robotnik's most famous machine in the entire Sonic the Hedgehog series and has reappeared in many other games such as Sonic & Knuckles, Sonic Advance and Sonic the Hedgehog 4: Episode I.
Sonic the Hedgehog (1991)
In the original Sonic the Hedgehog, the battle takes place at the end of the third Act of the Green Hill Zone on a flat piece of grass with two floating platforms above it. Dr. Robotnik will fly down the arena and drop the wrecking ball from the Egg Mobile. After that, it starts move on linear back and forth pattern across the screen, while swinging the wrecking ball from side to side.
To defeat him, Sonic must leap onto one of the floating platforms and then Spin Jump onto Dr. Robotnik's Egg Mobile eight times. The only thing the player has to look out is the wrecking ball itself, which swings towards the player on the platform, but the player is able to hide below the platform as well. After hitting eight times, it will destroy the Egg Mobile, as well as the chain and wrecking ball itself. Dr. Robotnik will flee, allowing Sonic to open the capsule, thus freeing all animals inside of it and having complete the zone.
In the original and numerous re-releases of the game, the player is easily able to get extra hits when Dr. Robotnik is moving down to the arena and before releasing the wrecking ball. In Sonic the Hedgehog Genesis, the player can do multiple hits by jumping and moving forward the Egg Mobile. In 2013 re-release of original Sonic the Hedgehog, battle arena has been extended to fit widescreen ratio of the re-release, while also the moving pattern of Egg Mobile with it's wrecking ball is slightly increased to move to another side at the time.
Sonic & Knuckles
The Egg Mobile-H later makes an appearance as a mid-boss (despite having normal boss BGM playing) at Sonic's story of Sky Sanctuary Zone in Sonic & Knuckles. It takes place on a similar arena with two platforms at the 1/3 point of the zone. Unlike in previous times, the Egg Mobile is this time piloted by Mecha Sonic, who flies down from the sky and releases the wrecking ball to swing it around.
The battle is mostly is similar like in original Sonic the Hedgehog, however the pattern of the Egg Mobile is slightly different. When Mecha Sonic arrives to the other side of the arena, he makes makes the Egg Mobile stop and then lets the wrecking ball swing to a very high height until it falls down the similar way and Mecha Sonic changes the direction. The player has to hit the Egg Mobile eight times while watching out for the wrecking ball's swinging. Like in the original Sonic the Hedgehog, the player can do extra hits before Mecha Sonic flies down to the battle arena. After eight hits, the chain and wrecking ball gets destroyed and Mecha Sonic escapes with the exploding Egg Mobile. The Warp Point will appear below the ground and can make the player progress to the higher levels of Sky Sanctuary Zone.
The Egg Mobile-H reappears in Sonic Advance. It is the first boss of X-Zone. Once again it is this time piloted by Eggman, with an appearance that has been taken directly from the original Sonic the Hedgehog. After running over crumbling bridge at the beginning, the player comes to the arena with two platforms, and a GBA remix of the boss theme from original Sonic the Hedgehog starts playing at the background. Eggman will fly down to the arena and then release the classic wrecking ball.
The battle against the Egg Mobile-H is slightly similar, even mostly easier than the original boss fight due having less than four hits to defeat it. However playing with Amy Rose, the player has to do Hammer Jump technique with Piko Piko Hammer into Egg Mobile in order to damage it. However, the player now is unable to deliver extra hits when the Egg Mobile flies down the battle arena. After four hits, the chain and wrecking ball once again gets destroyed while Eggman flies away with Egg Mobile.
Sonic the Hedgehog 4
The wrecking ball Egg Mobile is the boss of Sonic the Hedgehog 4: Episode I. It is piloted once again by Doctor Eggman in the boss act of Splash Hill Zone. Normally the battle takes place on similar wide arena with two platforms, where Eggman flies down with his Egg Mobile and releases the wrecking ball from the mobile. It then starts do normal swinging pattern back and forth. The player can easily hit the Egg Mobile from one of two platforms, while watching for the swinging wrecking ball.
Upon taking five hits of damage, Eggman will retract the ball and flip 360 degrees, slamming it down where Sonic is. However, this also leaves him vulnerable as he retracts the wrecking ball again, preparing for another attack. Doing another four hits makes the wrecking ball and chain explode and Eggman slowly escapes once again with his Egg Mobile.
The vehicle later appears again in E.G.G. Station Zone, as part of the boss rush before the final boss. The only difference in that zone is that platforms move up and down pattern, which can make little challenging. It also takes one hit to change its pattern to flip the wrecking ball 360 degrees. After hitting the Egg Mobile four times, the player moves on to the next boss of the zone.
In other media
Adventures of Sonic the Hedgehog
In the unaired pilot episode of Adventures of Sonic the Hedgehog, Doctor Robotnik starts chasing Sonic in a zone that heavily resemblances Hill Top Zone. Robotnik has a large wrecking ball (which is colored black and white) with chain add-on on his Egg Mobile, which he tries to swing toward Sonic during the chase. However Sonic easily dodges the wrecking ball and soon after takes it and gives it Robotnik to his hands. Sonic then tapes the whole Eggmobile along Robotnik and the wrecking ball, who then crashes to the tall mountain, thus completely destroying the Eggmobile with the wrecking ball add-on.
Sonic the Comic
The wrecking ball Eggmobile also appeared in an early issue of Sonic the Comic. Doctor Robotnik piloted the wrecking ball Eggmobile after brainwashing Tails and turning him into the cyborg Robofox. Robotnik nearly defeated Sonic the Hedgehog, who had been caught unawares by Robofox, until Tails broke through the brainwashing and destroyed the Eggmobile with a powerful Spin Attack.
A group of Badniks in the Marble Zone later had one of the checker-pattern wrecking balls (which they referred to merely as "one of [their] Master's weights"), which they threatened to use to crush the squirrel Tufftee.
In the Sonic the Hedgehog comic series, the wrecking ball makes an appearance (under the moniker of "checker-wrecker ball") in the first story of the original miniseries as one of the machines Dr. Robotnik uses in attempt to defeat Sonic the Hedgehog. It backfires however, when Sonic uses a Power Ring to defeat Robotnik, causing the wrecking ball to crush his Egg-O-Matic.
It is later used by Snively in the Genesis arc, after the world is reset by Eggman, but Sonic quickly disposes of the machine.
The Egg Mobile-H appeared in Sonic X #10 in the original Sonic the Hedgehog reality where it was confronted by Sonic in the Green Hill Zone.