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 in 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, which is short for Egg Mobile Hammer Ball-shiyou (エッグモービル・ハンマーボール仕様 Eggumōbiru Hanmābōru-shiyō?).
As the very first boss of the very first game, the Egg Mobile-H is arguably Robotnik's most iconic machine in the entire series. It has since reappeared several times, including in 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 Green Hill Zone Act 3, on a flat piece of grass with two floating platforms above it. Dr. Robotnik will fly down into the arena and lower the wrecking ball from the Egg Mobile. He will then move slowly back and forth across the screen in a linear pattern, swinging the wrecking ball from side to side.
To defeat him, Sonic must leap onto one of the floating platforms and then Spin Jump into the Egg Mobile. The only thing the player has to look out for is the wrecking ball itself, which swings towards the player on the platform, but the player is able to hide below the platform to dodge it. After hitting the Egg Mobile eight times, it will explode while the chain and wrecking ball get destroyed. Dr. Robotnik will flee, allowing Sonic to open the capsule, thus freeing all the animals inside of it and completing the zone.
In the original and numerous re-releases of the game, the player is easily able to get in extra hits while Dr. Robotnik is moving down to the arena before releasing the wrecking ball. In the 2013 re-release, the battle arena has been extended to fit the new widescreen aspect ratio while the movement pattern of the Egg Mobile and its wrecking ball has been increased in size to match.
Sonic & Knuckles
The Egg Mobile-H later makes an appearance as a mid-boss (despite having normal boss BGM playing) during Sonic's version of Sky Sanctuary Zone in Sonic & Knuckles. It takes place approximately one-third of the way into the zone, in a similar arena to the original fight. Unlike other versions of the battle, the Egg Mobile is now piloted by Mecha Sonic.
The battle is mostly similar to the original, however the pattern of the Egg Mobile is slightly different. When Mecha Sonic arrives at the other side of the arena, he stops the Egg Mobile and lets the wrecking ball swing to a very high height until it falls down in a similar way. The player has to hit the Egg Mobile eight times while avoiding the swinging wrecking ball. Like in the original Sonic the Hedgehog, the player can get a few hits in before Mecha Sonic releases the wrecking ball. After eight hits, the chain and wrecking ball are destroyed and Mecha Sonic escapes with the exploding Egg Mobile. A Warp Point will appear below the ground, allowing the player to progress to the next part of the level.
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 in the background. Eggman will fly down to the arena and then release the classic wrecking ball.
This battle is generally easier than the original Genesis boss fight, as it only takes four hits to defeat Eggman. However, when playing with Amy Rose, the player has to perform the Hammer Jump technique in order to deal damage. Furthermore, the player is now unable to damage the Egg Mobile during its descent into the arena. After taking four hits, the chain and wrecking ball once again get destroyed while the defeated Eggman flies away.
Sonic the Hedgehog 4: Episode I
The wrecking ball Egg Mobile is the first 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.
An edition of the Egg Mobile-H re-appears in Sonic Forces. In this game, the wrecking ball is replaced by a spinning saw blade. The player must hit it five times to defeat it. After it is defeated, Eggman will summon the Egg Dragoon.
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 piloted by a look-a-like of Eggman and confronted Sonic at the end of the Green Hill Zone. Despite concerns about how different "Eggman" looked and acted, and was hit twice, Sonic was able to defeat the Egg Mobile-H, causing the doctor to flee.