Pricey, but adds wonderful unique flavour!
According to Wikipedia:
"Black garlic is a type of aged garlic whose browning is attributable to Maillard reaction rather than caramelization, first used as a food ingredient in Asian cuisine. It is made by heating whole bulbs of garlic over the course of several weeks, a process that results in black cloves."
Its flavour is incredible and highly sought after by local chefs, for its distinctive umami quality.