For Spellcasters. This will appear as a crystal ball a bit larger than fist size. The ball will radiate magic, and will even pulse with a faint light. Testing will seem to imply this crystal ball works as a standard scrying device, allowing the user to peer across any distance, to see people and things that are of interest.
When first used when it matters, the ball will only show the spellcaster themself. The scrier can look from above, and from the side, from the front, back, or all over, but that is it. This makes the ball of little use, but the curse comes into play the next time the victim uses any kind of scrying magic, whether from a spell or another device; they will still only see themself, no matter how hard they try, or what kind of preparations they make. This effect will continue, even if they get rid of or destroy the cursed crystal ball.
It will require a successful high-level Remove Curse spell cast upon the victim, in order to be rid of the Narcissistic effect.
HD photo by connor bowe by connor bowe and HD photo by averie woodard by averie woodard under the Unsplash License modified in Inkscape by David