A NetHack tool that is basically a heavy white box (weighs 900 -- equivalent to one and a half suits of plate mail) that will stop corpses from rotting if you put them inside. They are rather rare, in my playing experience.

Although this item sounds like it could be useful, it isn't really. It's far too heavy to carry around, and besides, most of the time you consume corpses on the spot rather than needing to store them. For food preservation, a tinning kit or a ring of slow digestion is far more convenient.