requirements: advanced learning in alchemy, mining and meditation.
made of: golem mud or mandrake root or some Glitchy equivalent, which you can either discover or probably buy for outrageous prices from someone in the game. You can also find them them in Hell for reasons explained below.
they can sit on your shoulder, or ride around in a mini-me custom backpack.
the mud/root is animated by positive or negative aspects of personality, meaning they are either GOOD or EVILLLLL little buggers, and it's a coin toss which kind you get.
If they are good, every time you log back onto the game, you will have received notes about the good they have done while you were away, along with + points in mood and energy for you. If they are evil, you get the opposite kind of note, with a decrement in your mood and energy.
you can potentially change an evil one to good by doing good works yourself to offset things, but it's not guaranteed--or it takes a really long time, or requires some questing.
the evil deeds could be real, that is your friends/buddies might find that they have lost currants/energy/mood to your evil mini-me, or it has a negative impact on a tree or on the pigs in an area..that would make deciding what to do about an evil m-m more crucial. You might have to donate your m-m to a shrine to get rid of it. Of course, the good deeds could be real too, and that would make your buddies love your m-m as much as you do.
OR go for broke with the evil: take your evil m-m (only evil ones need apply) down to Hell and leave it there to stomp grapes for you. The short term gain slows your energy losses but drastically speeds up your mood loss, Down in Hell, your m-m gradually returns to its original state of golem-mud/mandrake rootness, where someone else might find it eventually to make their own m-m.