A "Tin Foil Hat" that shines bright in the light. (Disadvantage on Stealth Checks). When worn the wearer becomes immune to psychic abilities others try to force on the wearer (like mind control etc). Though the wearer does become more conductive, and as a result, is more likely to be very vulnerable to Lighting and/or electric attacks.  

Notes: Vulnerability: Lightning, Immunity: Psychic