The medal as seen in the camera footage.
The "Medal of Evil" is a medal that Lord Hater awarded Westley with after the latter's capture of Wander and Sylvia. This is the highest award a Watchdog can get, and Westley was hailed as a hero after he said "Hate's Great, Best Villain" with a raised fist.
The medal itself looks like a miniature version of Lord Hater's face doing an angry face, colored golden, while in the camera footage, it is platinum.