Claws of Frozen Rage CR 10
Any creature that enters or touches the area releases the consciousnesses of hundreds of executed rebels. Each manifests itself as a shadowy, clawed arm extending from the ice to attack the PCs and sap their strength. The shadowy arms extend from the nearest wall and can reach anywhere in the room. These shadowy manifestations cannot be damaged or destroyed, and only one attacks each PC. PCs directing attacks against the frozen corpses have no effect on the incorporeal touch attacks.
Pathfinder Module: The Witchwar Legacy . © 2010, Paizo Publishing, LLC; Author: Greg A. Vaughan.