Peter is a mask obtainable in Hotline Miami. The mask is of a unicorn and when Jacket wears this mask, guns get their noise generation reduced significantly. However, one must take note that it merely reduces and not completely removes noise from gunfire, meaning enemies in close proximity might still occasionally get alarmed.
This mask may be obtained by achieving a high score in chapter 11.
This mask is named after Peter Rasmusson, a friend to the developers and also the actor playing the pig butcher in the first Hotline Miami trailer