Glass Dip Pen, also called glass nib.
Glass dip pens are hand-blown and have a twisted glass tip that holds ink when dipped into an ink bottle.
 
Depending on the color, multiple sentences and even an entire page can be written with a single drop of ink.
 
The Glass Dip nPen can also be used with many colors from MM WaterColors. To do this, simply apply the liquefied ink with a brush - beware, it doesn't work with every color.... the proof of the pudding is in the eating.