Warden Meece is the warden in charge of Megakat Maximum Security Prison. Your stereotypical greedy and amoral Southern prison warden, he's been using prisoners to mine for diamonds which he uses to fund the prison - and, Callie suspects, to make himself rich. To speed up diamond production, he hires inventor Dr. Greenbox who creates an experimental laser-powered mining machine called the Gemkat 6000 (or "Jemkat 6000" as the blueprints we see call it).
Naturally, it's hardened murderer Rex Shard they choose as the test operator for thing. And naturally it goes wrong and turns Shard into a being of living crystal who turns everything he touches into non-living crystal, effectively freezing them in a state of crystalline suspended animation. After doing this to the two guys Meece assigned to watch over him, Shard marches right back to the prison and begins turning everything to crystal as Warden Meece, Callie and Dr. Greenbox cower in the Warden's office.
Even as the wall is turning to crystal, a visibly upset Meece is on the phone to the Enforcers. "Tell Commander Feral to get here, and fast!"
Sadly it isn't going to do Meece any good, nor is the imminent arrival of the SWAT Kats. After the wall has been crystallized, Shard shatters it by punching it and just walks in.
The Warden attempts to reason with him, but the convict turned supervillain isn't in a reasonin' mood and promptly grabs Meece, lifting up, whereupon he turns into a crystal version of himself.
Shard sets Meece back down on his feet upright, and for a moment everything seems fine, until the SWAT Kats come and interrupt Shard's attempt to do the same thing to Callie and Dr. Greenbox. A load of cement slugs from the Turbokat's cement machine gun knocks Shard into Meece's diamond vault (which is open for some reason). Callie heads outside to talk to them, while unbeknownst to them, contact with the diamonds has an... adverse reaction on Shard.
As he begins transforming further, a terrified Greenbox, backing away, bonks into Meece, causing him to teeter back and forth precariously.
As the scared scientist finally turns and runs from the room, gravity wins out and Meece's fate is sealed as he topples over and promptly shatters into several pieces all over the floor.
Now, at the end of the episode, after Shard is inevitably defeated, we see everything he'd turned to crystal revert back to normal - except for the prison, because since Meece went to pieces (haha, "Meeces to pieces!") then when he returned to normal... uh, yeah... that's gonna be one nasty R-rated mess.