Banner Ring of Doom (3.5e Equipment)
From D&D Wiki
Banner Ring of Doom: This variation of the regular banner ring automatically targets the closest most senior enemy leader whenever they are within a half mile of the banner when it is raised and affects them with the doom spell.
Faint (DC 18) illusion;CL 3rd; Craft Wondrous Item, Silent Image, doom; Cost 2,000 gp, 80 xp, 2 Days; Activation: See Text; Weight: — lb.; Market Price: 4,000 gp