This appears as an ornate square pillow, small enough to be carried in a backpack along with other equipment. It does not seem to radiate magic unless studied extensively, at which time, it's cursed nature may or may not be revealed (GM's option). It is made with silk, and fine threads, and remains full and comfortable no matter how long it has been compressed.
Sleeping on this pillow produces dreams of the "future". At first, the dreams come once per week. Then twice, then every night. The dreamer will see themself and their party members engaging in combat with various monsters and enemies, in various unfamiliar places. If the group is heading somewhere special, perhaps a dungeon or castle, the dreamer will see them all there, fighting for their lives; at least, that's how all of it will feel. The monsters seen in the nightmares will be random, though appropriate to the setting of the dream. Recurring nightmares happen, too, depicting the same horrible events, over and over, up until the point when the party finally arrives in the place dreamed about, at which time, other nightmares begin to take their place.
Understand, none of these dreams are true or prophetic, but they feel like they are. Whatever place was dreamed about, it will always seem like the place they have arrived in, even if it wasn't what they described to others before. What's worse, the nightmares rob the dreamer of rest. After having one, the dreamer can't get back to sleep.
Once the dreams are an every-night event, the character is exhausted all the time. They will have penalties on their statistics, Saving Throws, and all skill rolls. A spellcaster requiring rest in order to regain their magic spells, will be unable to do so. Getting rid of the pillow does not remove the curse, and the dreams will persist. Having slept on it even once is enough to impart this dreaded curse. Only a Remove Curse spell will free the victim, allowing a decent night's sleep at last.
Optional: If the dreamer is awakened during one of the nightmares, whatever monsters or creatures were in the dream immediately appear in the real world, and attack. In this case, it's as if they were summoned by a 10th level wizard.
Farwayart Ethnic woven pillow cover3 by Sr3207 under a Creative Commons Attribution-Share Alike 4.0 International License modified in Inkscape by David