Super Rat

This one isn't my fault.

— Ruby Gray 

Rats are a common species for testing and experimentation because some of their processes are just close enough to human that you can get a decent estimate of how we might react if exposed to similar things. For obvious reasons, these things are heavily controlled, and in this day and age we really have the tech to perform these tests without involving living creatures.
Still, it's a fairly simple starting place for those looking to start manipulating genomes and such. Not that I recommend this, but it's where most people start.
The particular batch described here was created by Galland Corp during their recent restructuring. They did a horrible job.

The Question of Superpowers

Even as they become more and more ubiquitous, people want more andd more superpowers of their own. Those who don't have them search for ways to gain them, while those who have them look for ways to get more. Or at least, some people do. And for those not willing to risk their own lives, the unscrupulous usually start with rats.
These rats don't technically have superpowers. They have been transformed and modified into a separate species that possesses enhanced strength compared to your typical variety of rat. They have the muscle mass to show it.
They also have implanted control organs in their brains. This is also shady, because if you were really confident in your work you wouldn't have to deal with the hassle that is mind control because your creations would be sane and hopefully content with what you're doing.
There hav been other people through the years who modified rats so they were enhanced, which included telekinesis, better intellect, sonic waves, etc. It rarely turns out well for the rats in the end and those experiments were abominations, but they were still more successful than what Galland Corp has turned out.
E/N: For someone who runs genetic experiments so frequently, you wouldn't think Ruby has space to judge, but she's got a lot of fair points here.