Theron's helmet is the helmetof the Argolin, THeron. Theron wore it when he waged a twenty minute war on the Foamasi. After there defeat it was hung in the main room of The Leisure Hive as a reminder that war causes destruction. It was removed from its place by Pangol, and used by him when he cloned himself using the Recreation Generator. In doing this all the clones wore exact replicas of the helm. Unfortunatly Pangols plans were ruined as the clones were not of him but of the Doctor. Gradually these images faded leaving but the original and one wore by the actual Doctor. The original was thrown by the Doctor at the screen of the recreation generator in an attempt to shut it down. It worked and the generator shut down.
Theron's helmet appears in The Leisure Hive.