Not necessarily a joke per say, but a thing my parents used to say last year when I was anorexic.
I'd be losing so much weight, which of course shows more muscle now that its uncovered. I was lifting wrong, eating wrong, just everything wrong. And I still had a bit of muscle being gained thanks to noob gains. Anyways each week as I lost a ton of weight thanks to anorexia :/ the tiny muscles would be a bit more revealing. My mother would always ask me in all seriousness, "Are you on steroids? You better not be doing any of that stuff".
Just thought it was funny, since the general public automatically assumes when someone is losing weight or gaining muscle their on roids.