The Disguise Kit is a Killer Box-exclusive item and cannot be found anywhere in the map.
The Disguise Kit allows the Killer to take on the exact identity of a corpse replacing their appearance and name with the corpse's. Doing this will mutilate the corpse rendering it unidentifiable.
(Notes: When you use the Disguise Kit you'll remove all of your traits. Also, when you mutilate a corpse, you'll make it impossible for Investigatives to figure out what wounds the body had as they've been skinned.)
KIRA Version[]
There's a special Disguise Kit that has a very low chance of spawning called the "KIRA Disguise Kit".
What makes it different compared to the normal Disguise Kit is that it has unlimited uses, and will make the corpse disappear with only the items of the victim being left behind.