The Writing Tool
In a place and time where the most common writing utensil is a a feather dipped in a bit of ink there were a few who, unhappy with the design, strived to find a new way to transcribe things. The fountain pen was invented by an artificer who liked the overall design and simplicity of the feather and ink but disliked how often they would have to buy new bottles of ink. The pen itself is a large sharpened needle typically used for knitting, fixed to it is a small vial of ink with a downward facing valve. The grip of the pen assures for better holding with a small button that releases a slow drip of ink when squeezed lightly. When held tighter the ink will come out faster. To solve the problem of having to constantly refill the ink the artificer essentially made the vial a bag of folding, despite its small appearance the vial can hold several gallons of ink at a time and the extra dimensional space of the vial keeps the ink from drying out. To refill the ink the side bar must be switched down to the safety position, you then unscrew the cap and pour the ink into the top. A major fault in the design the artificer soon realized, was just how long it took to fill up the ink cartridge.
As with most artificers the creator became a bit distracted with conflicting ideas as he made the fountain pen. He included a second feature referred to as "Vial Purge." When a person unscrews the top of the vial container, typically used for refilling ink and then pushed the side bar in the "up position" the pen will start massively evacuating its ink stores at roughly a gallon of ink every six seconds. Upon testing this feature the artificer found the Purge feature had significant kick back and devised a secondary locking mechanism if the needle end of the pen is stabbed into the ground. The feature will continue to go until either the ink stores are empty or the side bar is locked into the down position.
In World Impact
Generally this writing utensil has had little impact on the large world. Most find loading the pen with ink too arduous to consider it a full time writing implement. As for the second feature it has gained a surprising amount of popularity among adventuring types mainly due to the Purge feature. Apparently having a instrument that spews ink is advantageous against combatants that turn invisible.
"Oh I love that pen, best gold I ever spent. I have to tell you though I haven't filled it with ink in, oh... I don't even know how long. These days I prefer torch oil, much more flammable." -Robert Onceborn, Knight