Hair of the dog
Hair of the dog is an artifact. It has been long been regarded by many as a mostly pointless artifact, but it is rumored to have come from a legendary sea titan who owned many golden haired dogs. One day, as he was grooming them he realized one of them was missing a hair and immediately killed all the people in his castle who he thought might have been the cause. He then offered a sensational reward of a million gold coins or thirty gold bricks for the return of it. It never occurred to the titan that the dog actually had the missing hair on its tongue.
Alas, if only our heroes took time to read the posters that advertise this large bounty for its return. Instead, they usually just sell it for a handful of gold coins to the first shopkeeper who makes them an offer. If a hero's pet ever chews on the box, the hero will need to open it and then feed the item to their pet to counteract the deadly side-effects.