This is a muscle growth series focusing on characters from the entire universe of Sonic the Hedgehog, including the less known ones. Beta was technically requested by  backyardgameboy, but due to him/it being together with Retro, both Beta and Retro are to appear altogether as an entry.

Description:
Although the muscle growth, corruption and rampage stuff onto many Mobians near-worldwide came directly from three glowing strangely-carved stones, that wouldn't prevent stone holders from developing jealousy and rivalry towards each other, as well as the mix of pride, confidence and arrogance. Such was the case involving the purple stone holder Duck "Bill" Platypus and his muscularized army of platypus legionnaires, dingo soldiers, two of his fellow Freedom Fighters (Barby Koala and Walt Wallaby), a majority of many unfortunate citizens across Downunda, and the newly added Crocbot.

A month after the sudden takeover of New Mobotropolis, Nicole the corrupted Holo-Lynx, leading her muscularized citizens had so far conquered a dozen cities and towns neighboring the Republic of Acorn and so wanted to show that achievement off to her purple and red counterparts. With the help of the local film crew (also caught back in the exact day), Nicole had done the latter through an online video. As expected, Duck and Crocbot caught an eye on that video and were filled with jealousy, but without a good reason. Despite having taken over the entire continent, there were certain spots (hidden or not) that left Downundan Mobians unaffected and untouched. To ensure no bottlenecks in Duck's reign, Crocbot proposed having a sentient AI of their own, much to Duck's hesitance, noting that there were no known AIs across Mobius besides Nicole. Crocbot in response unveiled the computer left behind awashed by Miles "Tails" Prower, dubbed the "Build-it Box" by label on its plate door.

Despite being found floating at the northwestern coast of Downunda, the Build-it Box was surprisingly functional, owing its waterproofing mechanic to the aformentioned inventor. The only noticeable signs of life however was just a duo under one kind of computer virus. Crocbot had already interacted with them on that day, and was excited to introduce them to Duck. The smaller viral humanoid was Retro and the bigger one was Beta, both were eager to serve their new master, following the literal loss of Nominatus and his last violent interaction with other Mobians in Adabat. For the whole time, Retro was desparate to prove his worth but was patient enough to give Beta comfort as much as he wanted, as the bigger guy was so soft that he felt lonely. With the Build-it Box activated, Retro and Beta were printed out as their Mobian-sized physical forms, much to their joy of having a better output than one case of being printed smaller than they wanted, but it wasn't just the only thing Bill and Crocbot had in mind for them. With the power of the purple stone, Retro and Beta were transformed into their bigger and more powerful selves, but were even more surprised to receive unique powers of their own. Retro could now fly and hover to wherever he wanted, and Beta could grow or shrink into any tolerable size.

Although this time the two viral duo's personality remained unaffected by the stone, they were nevertheless programmed to serve Duck and Crocbot as their new masters, and although they felt compelled to serve Walt and Barby as well since they bore their big and muscular bodies, Duck encouraged them to treat the latter two as equals. While Crocbot was happy to have sentient AIs serve under his control, Bill longed to have companionship with them, recognizing the fact that Nicole had become way more powerful due to her control of and connection into the nanite-based system inside New Mobotropolis, in comparison to these two viruses who were mere mooks to the late Nominatus. The idea came to Duck that while Nicole had nothing to rely on except citizens in flesh, his army had also so far obtained a sizable amount of large machinery in which the two viruses could naturally and directly control, albeit only one at the time. Cooperation between one literal machination-controlling virus and any Mobian member could strike up as a unique trait for the whole Purple Stone army. However, Retro and Beta still had the ability to infiltrate small electronics, obliviously an exploit Bill and Crocbot could take on hideouts that relied on computers and networks.

Mobian Muscle Growth:
Speedy (Alt, NSFW) || Duck "Bill" Platypus (Alt, NSFW) || Jolt the Roadrunner (Alt, NSFW) || Razor the Shark (Alt, NSFW) || Eclipse the Darkling (NSFW) || Barby Koala (NSFW) || Walt Wallaby (Alt, NSFW) || Akhlut the Orca (Alt, NSFW) || Babylon Rogues (NSFW) || Crocbot (NSFW) || Silver the Hedgehog (NSFW) || Nicole the Holo-Lynx (Alt, NSFW) || Drago Wolf (NSFW) +Alt (NSFW) || Echo the Dolphin (NSFW) || Sealia Seal (NSFW) || Augustus the Polar Bear (NSFW) || Erma Ermine (NSFW) || Conquering Storm (Alt, NSFW) || Coral the Betta (NSFW) || Sleuth "Doggy" Dawg (NSFW) || Flip Penguin (NSFW) || Guntiver the Artic wolf (Alt. NSFW) || Queen Angelica the Anglerfish (NSFW) || Shift E. Wolf (Alt, NSFW) || Tex the Lizard (NSFW) || Fiona Fox (NSFW) + Classic (NSFW) + Payback (NSFW) || Amadeus Prower (NSFW) || Rosemary Prower (NSFW) || Leeta and Lyco Wolf (Classic, NSFW) || Retro and Beta (NSFW) || Helmut von Stryker & Harry (Alt, NSFW)