Chekov's Spell -- This spell has a two-fold effect. The first is to make the target item almost-unnoticeable to anyone not specifically looking for it. The second is that someone who has seen the item will remember it when they encounter a situation that would be perfectly solved by use of said item.
A tribal society which lives on the harsh Northern Plains consider it dishonourable to slay an enemy without looking it full in the face. Any missile weapon is treated with derision and contempt, while rangers and other archers are denied entrance to the tribal villages.