The Coat is a equippable item that can be found in the Botany classroom and in the Tailor shop.
When a player equips the Coat, their shoes will be replaced with dark gray shoes, and their shirt and pants will be covered up with a large trench coat. This will effectively limit the number of identifiable fibers that will be dropped.
When worn with a Mask a full disguise will be worn in that players will be unable to tell exactly who you are, nor will any fibers that are part of your original appearance will be dropped*.
The Coat can be dropped by the Killer Box.
*May not apply if you're using the Clown hat or the Disguise hat.