Brainerd Byring, a brave and efficient second lieutenant was guarding his men in the woods of West Virginia for any surprise attacks. He positioned himself nearby on a rock. He was strong but could not evade the strangeness in the air of the woods.

Suddenly, he saw a dead body of a soldier lying near him. His mind starts playing tricks and an unknown feeling grips his mind and body. The more he concentrates on the dead body, the more he feels the heat in his body. Night passed and in the morning Byring's dead body was found by his men.

What killed Byring? Was it an apparition or a psychological fear in his mind? ( )