Per 
SCP-5439
Class: Keter
Containment procedure(s):
Anomaly is contained in a 5m×5m×5m concrete cell and has a constant supply of D-class personnel trained to notice subtle mutations in the faces of their familiars.
Description-
SCP-5439 s a Keter class parasitic anomaly, with its hunting involving familiarity. It takes the form of one of the subject's acquaintances but is sure to make one small, subtle change to their appearance. Is the subject does not notice the difference within 120 hours of first contact, it kills and eats said subject. The subtle difference varies based on the subject's familiarity with the acquaintance, with more familiarity equating to a more slight difference.it stays in the host's form while eating the subject. If the targeted person notices and remarks on the mutation, SCP-5439 walks away and disappears
