Answer:
I run around the city, but I never move.
I'm white, I'm round, but not always around. Sometimes you see me, sometimes you don't.
i'm popular for Knuzlocks what am i
All about, but cannot be seen, Can be captured, cannot be held, No throat, but can be heard.
Gets rid of bad ones, short and tall. Tightens when used, one size fits all.
You use it between your head and your toes, the more it works the thinner it grows.