Peel off the outer layers of the Garlic (6 bulb) so you're almost to the cloves, then use a damp paper towel to wipe off any dirt.
Place the garlic root side down in the rice cooker. Make sure your rice cooker is plugged in and on the "warm" setting, and set a calendar reminder for 2 weeks from now! If you are doing more than one layer of garlic, make sure to rotate the top and bottom bulbs every few days so that they can all heat evenly.
Check on them after a week or so and do a taste test, since time will vary based on rice cooker temperature and the amount of garlic you use. If you have a particularly low heat rice cooker, this process can take up to 3 weeks.
When tasting, pull off a clove, peel it, and take a nibble; the desired result is black, sweet, tangy and a little chewy (a little softer than a gummy bear), with a richness almost like a balsamic glaze.
Enjoy your black garlic! Stored in an airtight container, it will keep for up to 6 months in the fridge. Peel it all at once if you want to take a pretty picture, otherwise just peel the cloves as needed.