My idea is that of an automated physician of advanced manufacture, able to diagnose and treat a wide variety of human diseases. Classification Euclid, containment measures as would be necessary to keep, say, a grizzly bear contained.
Memetic properties of the object include the ability to appear 'human' to any person within its visual range. Photographic and video equipment will always reveal the robotic being underneath.
The being is clearly sentient, able to learn new information in very human like ways, and capable of generating new insight and creativity despite the absence of any biological components. It is emotionally intelligent, but displays only very simple emotions itself.
It is aware of its cybernetic nature, and cooperative with interrogation, but resists containment on the grounds that wrongful imprisonment is a violation of its lawfully guaranteed civil rights, granted by a UN resolution in 1989. It insists that it has been operating continuously for 25 years, and was manufactured in Tempe, AZ. Subject can be provoked by physical force, threat of deactivation or disassembly, or by being referred to as a 'robot', a term it considers a racial slur.
Despite the ability to perform advanced surgical procedures, the unit has proven unable to repair itself beyond the simplest routine lubrication.
I realize I might be treading into 'character sketch' territory here, so, feedback is wanted.