Panty & Stocking with Garterbelt

Synopsis

Stocking finds herself gaining weight and goes on an intense diet, but she only keeps getting fatter until she balloons into a giant. When the cause is revealed to be from an obese Ghost who refuses to diet, Stocking sets out for revenge. Upon defeating the Ghost, Stocking returns to her original figure.

Daten City High School holds a lingerie run in which participants must race in their underwear. The run is interrupted by a Ghost who eats underwear, including Panty and Stocking's weapons, so Panty must resort to using whatever underwear she can find.

(Source: Wikipedia)