Dust of disappearance
From Ardrana
All things touched by dust of appearance reflect and bend light of all sorts (infrared and ultraviolet included), becoming invisible. Normal sight can't see dusted creatures or objects, nor can they be detected by any normal detection or even magical means.
Invisibility bestowed by the dust lasts for from half an hour to perhaps three hours. Unlike the invisibility spell, dust of disappearance remains effective even after an attack is made.
Note: This item originally appeared in the 2nd Edition Dungeon Master Guide for the Advanced Dungeons & Dragons game by TSR. Their inclusion here is for the purposes of providing context for the campaign only.