Greetings I am Rin, I decided to take various ideas I had for SCP objects and record them here. I don't expect most of these to be published to the main site (some I feel need to be expanded though I am unsure how at this time). If you have any feedback please message me, I am open to alterations on my ideas.
rating: 0+x

SCP-5635 next to 2 normal prosthetic arms.

Item #: SCP-5635

Object Class: Euclid

Special Containment Procedures: All instances of SCP-5635 are to be stored in a climate controlled vault. The vault is to be guarded by two (2) level 3 security personnel and all instances must be cataloged on a weekly basis. Instances may only be removed for testing and require approval by site command, these removals must be logged and monitored to ensure they are returned to the vault. Due to the limited supply of D-Class personnel who are skilled in the use of prosthesis, all subjects involved in SCP-5635 testing must be recent amputees (1 month max) or have their arm surgically removed. Proposals to use SCP-5635 on foundation personnel are pending.

Hospitals should be monitored for any potential instances of SCP-5635 by MTF Epsilon-4 ("Night Nurses").

Description: SCP-5635 is a collection of ██ prosthetic arms, each one designed to be placed on a elbow mount. Each instance has an outer layer composed of a plastic like material ending with a hand on one end and a cupped section on the other. MRIs of the instances have confirmed an organic mass on the inside of indeterminate origin. Proposals to collect samples from the inside are pending. When the cupped section of SCP-5635 is placed against the point where a subject's arm is missing (can be from a wrist to shoulder) SCP-5635 will instantly fuse to the subject's body often causing extreme pain and rendering the subject unconscious. Attempts to place SCP-5635 against any other portion of the body or on a leg/hip do not create a reaction. SCP-5635 applied to a corpse will also not result in a reaction. Over the course of the next few hours SCP-5635 will begin to morph to match the subject's missing arm. It will lengthen/shorten, widen/thin, etc along with the fingers and thumb reorganizing if it is placed on the opposite arm (eg a left instance being placed on a right arm). The plastic will also start morphing, changing into skin that matches the subject's skin tone. Details like tattoos or other body modifications will not be replicated. During this process the organic matter inside SCP-5635 will dig it's way into the subject's body connecting to nerves and blood vessels. Once this process is completed SCP-5635 will perfectly match the subject's missing arm and will be fully functional to the subject. Skin samples taken from SCP-5635 will match the samples taken from elsewhere on the subject. While being nearly indistinguishable from a real limb, X-Rays will show a lack of bones and rather a single mass of flesh. Subjects given an instance of SCP-5635 have a higher metabolic rate equivalent to the size of the limb SCP-5635 replaced. Despite this, SCP-5635 is not stronger then the subject's arm would normally be and shows no external anomalous properties.

SCP-5635 to this date has not been removed without the patient dying, normally of blood loss. When attempting to surgically remove SCP-5635 from the subject the veins and nerve endings show increased resilience and regenerative capabilities often reattaching before the operation is complete. Upon death SCP-5635 will start draining as much blood as it can from the subject into itself and start to transform back into it's original form. Once it's physical form has returned it will disconnect the nerve endings and blood vessels and retract into itself, closing off the cupped end and entering a dormant state. This dormant state will persist until the Instance is placed against another subject and the process begins again.

Addendum 1: Excerpt from experiment log:

Experiment #:9
Subject: D-49871
Experimenter: Dr. A████
Procedure: Subject is to be sedated and have their right arm surgically removed. SCP-5635 will then be placed on the newly formed stump before the subject is allowed to regain consciousness. Test will then continue to observe changes in the subject until standard termination.
Results: Surgery and application of SCP-5635 was a success, subject regained consciousness a few hours after SCP-5635 finished it's process. Subject noted a strange feeling in his arm but it passed after a few hours. Subject was then closely monitored after being reintroduced to D-Class population. Subject showed no losses in abilities and was able to pass physical tests provided. Upon end of month termination SCP-5635 returned to it's inert state and was re-contained.
Site Director's Notes: Requests have come to repeat these types of tests. Due to the nature of SCP-5635 and the difficulty identifying an instance in an active state only 1-2 instances may be used at the same time and D-Class subjects used are to be exempt from other SCP testing.