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.
In a city where the justice system features judicial dueling, plaintiffs and defendants are permitted to request a champion to take their place in the duel: Someone chosen by lot from among the foreigners in the city. When anyone first arrives, they are given an enchanted ceramic pendant that marks them as a candidate for "court duty".
Wealthy folk entering the city are often escorted by burly guards, paid to carry pendants on their behalf: They elude court duty in that way.
Adventurers may seek work as a rich man's proxy or may find themselves magically summoned to serve as a champion.