From Arkham Horror Wiki
A Corrupting Influence is an Exhibit Encounter card. It first appeared in The Curse of the Dark Pharaoh (Revised Edition) expansion.
Someone close to you has been corrupted by the Pharaoh's dark power. You must either return one of your Ally cards to the box or raise the terror level by one. Then gain an Exhibit Item.
Move the Ancient Whispers marker to the Downtown Street Location.