Beware of Archmages who haven't had their morning tea.
Beware in particular those Archmages who, not having their morning tea, are too cranky to properly light a fire and, in their frustration, lash out with whatever spells the have handy just to "get the godsdamn kettle to boiling."
Fun fact: Fireballing your kettle, while emotionally satisfying, evaporates the water and you are still without tea. And probably a fireplace.
The wizard Ehrynn Paahlet was one such Archmage, and while her fireplace was being rebuilt in the aftermath of her latest incendiary tantrum, she had An Idea about How To Fix This Problem Once And For All. She promptly assembled a group of hardy adventurers and disappeared for several years. When finally she returned, her mood was much improved, and the countryside breathed a sigh of relief as her morning tea never failed to boil.
Of course, her tower burned to the ground six months later, but that's beside the point.
Ehrynn's Perfect Match is a rod of gold, approximately the length and width of a pencil, flat at one end and tapering at another. It is found inside a storage tube made from the thighbone of a large creature, and the bone itself is carved with ornate runic script. The bone tube radiates abjuration magic, and the golden rod of conjuration.
Operation is simple: grasp the rod by the flat end and withdraw it from the bone tube. The tapered end will immediately burst into flame and will burn continually: in the fiercest of winds; in the rain; underwater; smothered in sand. The Match does not simply create fire; it actually opens a minute gate to the Elemental Plane of Fire. The only way to extinguish the match is to drop it into its bone tube, or otherwise place it within an object or location warded against extra-planar effects.
However, there are two drawbacks to using this device. First, there is no way to adjust the flow from the gate; it cannot be used as a torch, flaming weapon, or cutting tool. The only thing it does is extrude Elemental Fire at a precisely controlled rate.
The second drawback, though, is related to the first. Ehrynn knew that there would be times when she would need a hotter flame, and therefore the longer the match is left outside of its tube, the hotter the flame becomes. Given enough time, the Perfect Match will set fire to anything. Rocks will melt and even metals will ignite if exposed to it long enough. Fortunately, he metal of the Match is immune to this melting effect. However, Ehrynn failed to take into account that even without melting, its metal construction would become very, very hot...
Every round after the first that the Perfect Match is lit, it deals 1 hit point of fire damage to anything touching it. This effect is cumulative until it reaches 30 hit points/round, which is the maximum damage from exposure to the Plane of Elemental Fire. When this occurs, a safety effect disengages the planar gate and the Match begins to cool, again at a rate of 1 hit point per round. Placing the Match back inside its bone tube resets it, and it will again ignite upon withdrawal.
This is my entry for the Amazon PayPhrase Create-a-Thing Contest.