Pint-Sized Slasher mask

The Pint-Sized Slasher Gear, which you will obtain during the tranquility lane quest, if you decide to help betty to kill all residents of Tranquility Lane, consists of a knife which has a lot more power than a normal knife, but the power is unknown, and higher critcal chance, and a clown mask. You do not keep these items, as they are taken off of you at the end of the quest.

One of the newspapers shown when loading saved games mentions 'The Pint-Sized Slasher' in a side story.