Kokubu Karin was just your average junior high school student, that is, until she turns into superheroine Super Pig! [or Buurin] Years later, however, instead of fighting crime, she fights for another day to live. [Though, I don't think old pig tastes very good, does it?]

More info on Super Pig if you're interested:
http://www.geocities.com/Tokyo/6707/index.e.html

References used via skimming through google image search for "Charlotte's Web" and "Old Pig/Pig"