ToME WikiOrvin: In IdeaArchive/Items/Precognition split up into parts or levels, NeilStevens wrote about the Ring of Precognition: "Right now it's a special thing to get. It'll give the player a thrill to find. I'd like to keep thrills like that, and in fact expand on them." Here is a possible additional thrill, the rare artifact
Mirror of X:
Upon activation, it causes a random (say 2-6, perhaps depending on magic devices skill) number of "images" of the player to appear nearby. These images move around randomly, are not controllable by the player, and cannot do anything other than move around. However, monsters mistake them for the player and will divide their attacks among them. Images have the same AC, saves, and other stats affecting whether they are hit by attacks as the player. Images remain for a pre-determined duration, but monsters have a chance each turn of realizing an image is false (and thereafter not attacking it). This chance could be determined as follows:
chance=max(5%, 10%+modifiers), where modifiers are:
if monster is confused, -25%
if image is in dark square, -10%
for each glass wall within 3 squares, -2%
if monster's attack "hits" image, +25%
a modifier based on monster's intelligence