Silvered mirror in a simple frame
This mirror is created by flattening an eye from an umber hulk and sandwiching it between the glass and silver layers of a mirror. Once prepared, the 4th level wizard spell Confusion can be cast onto the mirror. After the casting, the mirror must be immediately covered in a fine silk bag to prevent its unintended activation. When desired, the mirror can be removed from the bag and shown, thus triggering the spell on all who gaze on it (note this is more powerful than the spell which only affects 1d4 creatures).
If the mirror is presented to some unsuspecting victim (as a gift for example), the individual will receive a -4 penalty to the save because of proximity and the predisposition to look directly at it.
Once used, the mirror shatters and is destroyed.