A thermos of warm soup.
Elixir Soup: A hearty and filling soup made by Link’s Grandma that heals both body and spirit. Link must bring a fairy to his ill Grandma to cure her before she is well enough to make his favorite soup. Once she is better, he can always stop by for a refill of soup in an empty bottle. One bottle holds two servings of soup, so Link can refill his hearts and magic twice before running out of that delicious soup.
This container represents a perfect pairing of the scientific and arcane arts. The flask can keep any fluid hot or cold for ages. As long as the flask hasn’t been opened, the contents are kept at whatever temperature they were when the flask was sealed.
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Many a fantasy adventure includes some version of the ever-chill mug. The frost-ale mug from Planescape: Torment is the only one I can think of right now, but I know there are many more.
Be excellent to everyone.
-Ceph