Cursed Sea Chest of Sinking
Opening the simple clasp reveals a blue velvet lined interior. Perfectly dry and in like new condition. As much as the exterior remains ever soggy the interior is kept magically dry. Even if the chest is submerged or liquids splash into interior. Wet things placed within will rapidly dry out. Note: liquids in bottles or other containers are safe.
Surely a useful item to have onboard! Except any boat, ship, or other water craft on which the Soggy Sea Chest spends more then a few minutes will sink. The sinking occurs slowly, starting with a few leaks, which gradually grow more frequent and larger. Depending on efforts to of crew it may take up to a week for a large ship. Once sunk the ships wood, rigging, sails will rapidly rot and it's metal fittings will quickly corrode. This process is inexorable, continuing even if the chest is removed. If vessel is beached, dry-docked, or similar the materials will still slowly decrode until there is nothing left.
Fun to fill with cheap treasure and give to your least favorite local pirate.