(Loosely inspired by a kind of plant in Dwarf Fortress and a separate idea about prophesy.)
Eye Fruit are a parasitic infection of fruit trees that cause one or more of the fruit to turn into large eyeballs, complete with a fleshy eyelid. Hirelings and henchmen must make morale checks when discovering a tree with eye fruit during the party's travels.
A magic-user who plucks an eye fruit, casts Charm Person on the fruit, and squeezes the juice onto the soil around the roots of a living tree has a chance (5+ on d6) of infecting the tree with a charmed parasite. The magic-user can focus for a round to see out of the "eyes" of that tree.
After eating an eye fruit, a character will have a vivid, disturbing dream the next time they sleep. Determine the components of the dream in any random manner desired. For the next week, roll a d6 every day: on a 5+, one or more of the events in the dream will come true that day. Give any encounter a 5+ chance of having part of the dream come true; if there are no encounters that day, or none of them included elements from the dream, there is an extra encounter at the end of the day that is completely defined by the events in the dream. From the character's point of view, this is a prophetic dream, even though mechanically, eating the fruit causes the events to happen.