Bag of holding
From Ardrana
This bag appears to be a common cloth sack of about 2 feet by 4 feet size. The bag of holding opens into a nondimensional space, and its inside is larger than its outside dimensions. Regardless of what is put into this item, the bag always weighs a fixed amount. If overloaded, or if sharp objects pierce it (from inside or outside), the bag will rupture and be ruined. The contents will be lost forever.
Note: This item originally appeared in this form in the 2nd Edition Dungeon Master Guide for the Advanced Dungeons & Dragons game by TSR. Their inclusion here is for the purposes of providing context for the campaign only.