A basketball sized can that can diffuse up to a typical lightning bolt's worth of energy into gamma rays. In 100 words.
This ever-full, ever-surprising, ever-ridiculous flask contains a magical liquid that may be the best or worst thing you've ever drank. Handling with caution won't do you any good.
100 word magic item
The King always has the coolest form of transportation.
Combating any monster is often as simple as having the right tool for the job. The nightmarish lycanthrop is no exception.
These relatively plain silver rings allow the wearer to go unseen, unheard, and un-smelled and render the wearer completely intangible - but only to others who wear a Ring of Mutual Exclusion.
A longsword that lashes out in the hands of a graceful warrior.
The two gently-humming, crystal-studded blades are semi-transparent and sharpened to a deadly razor edge. The haft between the blades is decorated with brilliant multi-colored crystals. The balance and craftsmanship are perfect. You feel that these trusty blades will never fail you.
To purify the water from a certain river the monks have carved a section of the river that goes over a stone bed. Through holy carvings of gods, godesses, and holy symbols and then the river flowing over them, it purifies the water making it safe for drinking and/or makes it holy water. For rivers that do not have natural rock bottoms, large smooth stones can be carved and added to the water to fully cover the bottom.