Pint-Sized Slasher

The Pint-Sized Slasher, was a pre-War 21st century serial killer that wore a creepy clown mask, and doned a large chef knife as his signiture killing tool.

You are able to pose as him in the mission Tranquility Lane, as you have to kill all residents while posing as the killer child clown himself. This could possibly be a reference to the movie Halloween where Michael Myers began murdering people as a child with a knife and a clown mask

Trivia
One of the newspapers shown when loading saved games mentions 'The Pint-Sized Slasher' in a side story. As well, the full article can be accessed via the Capitol Post newspaper office in L'Enfant Plaza.