Pepperoni is a kind of American sausage that was developed by Italian immigrants. It is most commonly found atop pizza, but sometimes makes it way onto sandwiches and crackers. A graphic version of it can be found on some soda cans and on the Japanese flag.
Pepperoni is kind of horrible on its own. In modern day, it's used primarily as a classic decoration on pizza. It generally produces an excess of grease and makes a mess. Despite its drawbacks, its manageable size and iconic red, circular shape contribute greatly to its continued popularity.
Pepperoni became an official snack on April 24th 2013.