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.
Enraged by the violation of the Peace Pool and the Whalebone Forest, a dead leviathan has risen from the bottom of the ocean and now hounds ships around the port where the stolen jewels went to land. It capsizes ships and devours sailors whole, spears protuding from its dead and crab-eaten hide.