Classification: Euclid

Special Containment Procedures: SCP-XXXX is to be affixed to a wall by 3 restraints made out of tungsten steel in order to prevent mobility. These restraints are not to be removed for purposes other than research or replacement due to corrosion, which must happen bi-monthly
The cell in which SCP-XXXX resides in is to be cleaned thoroughly thrice a week by two (2) D-Class personel wearing acid-resistant clothing and a security guard monitoring the process is to be positioned outside the door.
Establishing physical contact with SCP-XXXX is prohibited outside of research, and all attempts to do so are means for termination.
Instances of SCP-XXXX-1 are to be contained on an on-site psych ward for research purposes until they expire, after which the bodies can be dealt with without special procedures.

Description: SCP-XXXX is a 150 centimeters long, dark green severed tentacle, anatomically similar to that of Octopus vulgaris. The surface of SCP-XXXX is coated with an oily layer of mucus, while the severed end of SCP-XXXX is constantly leaking a black substance with mildly corrosive properties and the viscosity of blood.
SCP-XXXX is capable of locomotion and will try to grab and wrap itself around anyone who comes near, if it hasn't already. It is strong, capable of easily breaking human bones by crushing, but it isn't strong enough to breake most metals.
The skin of SCP-XXXX is tough, and cannot be penetrated or cut with any known means.

SCP-XXXX posesses sentience, and when a living human comes into contact with SCP-XXXX, it will attempt to telepathically persuade them to allow SCP-XXXX to take control over their body.
If the subject refuses, SCP-XXXX often may try to either kill them in what is presumed to be anger and frustration.
However, if the subject allows SCP-XXXX to take over their body, SCP-XXXX will quickly wrap itself around the subject, and then attempt to enact a ritual (see Addendum-XXXX-1) to open a transdimensional rift, which it will then attempt to walk into. Through this rift, a mass of similar tentacles protruding out of a central mass can be seen.