Hard-Boiled Heavies

"A powerful robot army built by Dr. Eggman. Loyal to his orders, the Heavies successfully retrieved the mysterious gemstone, but its power seem to have loosened a few of their screws."

- The Sonic Mania manual description of The Heavies.

The Hard-Boiled Heavies (ハードボイルドヘビーズHādoboirudohebīzu?), or HBH for short, are a group of elite robots under the command of Dr. Eggman. After getting struck by the power of the Phantom Ruby, they became surprisingly intelligent and strong, going over the standards of what Eggman thought they were capable of.

They were created by Christian Whitehead, and their theme song was made by Tee Lopes and Falk Au Yeong.

Creation
Interestingly enough, the concept for the Hard-Boiled Heavies was created when Christian Whitehead imagined that Dr. Eggman slumped into a depression after the events of Sonic the Hedgehog 3 & Knuckles and wouldn't even try to go after Sonic anymore. Instead he would just chill at home in his pyjamas. Meanwhile his abandoned Eggrobos would “go a bit mad”, which sparked the idea of the Hard-Boiled Heavies.

Sonic Mania
The Hard-Boiled Heavies were originally a group of five normal Eggrobos that served Dr. Eggman, and were sent to Angel Island after Eggman detected a powerful energy residing there. When the Eggrobos unearthed the Phantom Ruby, which was the source of the reading, it’s energy transformed them into powerful elite robots with different personalities and unique abilities. The HBH returned to Eggman with the ruby but their rebellious antics made it difficult for the doctor to control them. So Eggman snatched the Phantom Ruby from the Heavies, which sent them on their way.

The Heavies would then attempt to destroy Sonic the Hedgehog and his allies within various Zones, only to be defeated each time before returning to the Titanic Monarch Zone. During the battle against the Phantom Egg, the heroes might be sent to briefly fight the HBH once more, except now they have been enchanted or transformed further by the Phantom Ruby’s power. Afterwards, the transformed Heavy King betrayed Eggman and attempted snatch the Phantom Ruby for itself. However both villains were eventually defeated by Super Sonic.

Trivia

 * Heavy Rider’s Motobug, Jimmy, is named after “Polygon Jim”, A Sonic fan and game modder who passed away in a car accident. Polygon Jim was well known for creating a Sonic game mod that made a Motobug as a playable character.