Answer:
They would wear very frightening masks to scare the evil spirits away. They believed that evil spirits caused illness.
Explanation:
The False Face Society was an Iroquois healing group. The Iroquois False Face Society knew they could not kill a bad spirit. Their job was to scare the bad spirits. They used masks and chants and rattles and dance to scare the evil spirits and to chase them away. One bad spirit was the flying head.