 Item Number – SCP-4135 Object Class – Ketter Special Containment Procedures – Mobile Task Force 571 – Codename – Duck Hunt is dedicated to the location and containment of SCP-4135-P instances that manifest. The International Mallard Location Index is designed to track the activity of any specific member of the family Anatadi. Containment of the SCP-4135-P instances considered priority 1, and containment of the SCP-4135-A instances considered priority 7. Once the SCP-4135-P instances confirmed to be contained, the SCP-4135-A instances to be administered amnestics and released into society. Currently, an SCP-4135-P instance is located within Site-55 in a biological anomalous entity chamber. The chamber is reinforced with steel, and is to be repaired upon signs of damage. Once the current SCP-4135-A dies, the chamber is to be emptied of any duck viscera, and the new SCP-4135-A is to be located by Mobile Task Force 571. Description – SCP-4135 is a phenomenon that affects one random human on Earth, designated SCP-4135-A instances at any time. SCP-4135 is observed through the spontaneous manifestation of any member of the Anatadi family, usually of black colorization, near SCP-4135-A, designated SCP-4135-B instances. SCP-4135-B will then attempt to kill SCP-4135-A through any means necessary. SCP-4135-B instances are resistant to physical trauma and quickly recover from most injuries dealt to them over a small period of time. SCP-4135-B instances have shown not to require food, water, or oxygen to survive, and can survive an atomic blast, see attached to Document 73, Manhattan Project, and SCP-4135. When an SCP-4135-B instance is trapped, such as if it is in a container, it will bash its head against the walls of the container until the container breaks. Once the current SCP-4135-A dies, the SCP-4135-B instance will also die, and almost instantaneously, another random human on Earth will become SCP-4135-A. SCP-4135 usually targets people ages 18-35, but there have been cases of it targeting children and elderly people as well. Despite being virtually invulnerable, SCP-4135-B instances are no more deadly than the average member of its species. Because of this, SCP-4135-A instances rarely die from SCP-4135-B, and instead die of natural causes.