When discovered on MRI's or x-rays, medical staff will not necessarily bring these unexplainable objects to the attention of the patient. Implants may be composed of a variety of metals or other materials found on Earth. However, the underlying atomic structure of the molecules wrapped with other substances may be a technology not yet known to exist on Earth. Some implants form a bump under the skin. Upon having the bump removed, people learn that it contained a softer, spongy material of unknown origin.
Most people are at a loss to conjecture about the purpose of such a spongy material.
Based on their metallic qualities, it is speculated the implants may be transmitters, receivers, tracking or communication devices. As a transmitter, information could be sent from the Aliens to the abductees alerting them to an impending abduction. Information transmitted could wake the abductee up to a conscious level, a particular dream level, or to an out of body state. Alert abductees would sense something an internal change. Many abductees believe they can sense that an abduction will occur that night when they are sleeping.