Midnight Oil is produced only by Midnight Dragons. Due to this, it is incredibly scarce. It is not sold in the Market or anywhere, as the Midnight Dragon is an endangered species. However, it is often collected for use by those who house midnight dragons in their parks.
Though this has not been clinically proven, many wizards claim Midnight Oil induces a state of alertness, improves concentration, and helps them to work through the night without ill effects.
Wizards use Midnight Oil to stay awake all night while retaining full concentration and brain function. In wizard schools, Midnight Oil is incredibly valued by students who put off their assignments too late. They can also be used in certain potions.