Walter is interviewed by a psychiatrist that wants to send him back to the mental institution but he does not disclose that he is haunted by a mysterious man. Meanwhile the young boy Aaron flees from two bullying boys and hide himself in a tunnel in a park. However the boys find him but are surprisingly decomposed in seconds by a fungus. The Fringe Division is assigned to investigate and the boy is sent to Walter's laboratory to see whether he is also infected. Soon Walter finds that the fungus are part of a single organism that he calls Gus and they are interconnected with the boy. Written by Claudio Carvalho, Rio de Janeiro, Brazil