I first read "an abominable sewer mutant" as "adorable sewer mutant" and I think your picture bears that out.
Please to Be Working out with Boris
"Let's go, lady mutants! And squat. Glutes out, as if touching them to the back wall of the sewer, and don't get those knees too far in front of your paws! Use that tail for leverage! Want to protect your ragged, sewage-covered, and tattered claws! And curl! The bone! And curl! Don't get any momentum, ladies! Curl just from your wrist, like me!. If your bone is too heavy, drop it and use an old head you have lying around or just your body weight Remember, it's the diseases that are bloating your stomach, it's not YOU. --pbbbbt-- Oops! Sorry about that. It happens when I squat--let's just chalk that up to sewer gas, ladies!"
"Remember that the only thing standing between you and a perfect body is your self, and also anyone who comes in here and sees us and shoots at us, and then we have to eat them, and that's very tempting when we're trying to stay svelte.
"You want calves like this? Well, at least my left calf? Don't look at my right calf. I favor my left after a run-in with that puke golem down here. But my left calf is solid gristle, mutants! Now balance! Balance on the rotting putrid wood! That's core strength, vermin, and breathe in through your nose, and out through your gaping maw!"