Mix (stylized as M!x), is a breeding mechanic where an offspring share visual body traits from their two parents. A Tamagotchi born from the result of m!xing is a unique Tamagotchi Subspecies known as a My Tama (ナウたま Nautama).
The feature was first introduced in the 2016 virtual pet Tamagotchi m!x. The mechanic is also featured in the 2018 virtual pet Tamagotchi On, with over a thousand combinations more than its predecessor. In addition, Tama Pets are now capable of m!xing as well.
M!xing is a cosmetic visual feature for offspring Tamagotchis. When two Tamagotchis marry, their offspring will take the form of a completely new character with genetic traits shared from both parents. A My Tama can also pass their visual traits to their offspring with another character. In this case, a My Tama may only share traits with their offspring with only the current visual features they currently possess. However, some traits from previous generations may become latent and suddenly reemerge later.
M!xable body parts include four key components: the body (head, torso, and mouth), eyes, headgear (such as hair, ears, or hats), and miscellaneous accessories (such as wings, capes, tails, etc.). The My Tama's body color is also affected, where the offspring could inherit either parent's colors, combine both parents' colors into one blended color, or be a completely random color. The My Tama's outline color can also be influenced (for example, if it has Ura Tamagotchi genetics). The genetics it inherits also influence its likes and dislikes for food, clothing, and items, as well as its waking and sleeping times.
Some marriage partners have restrictions about which genetic traits can be passed down; for example, Hello Kitty will never pass down her eyes or body shape, and only her bow and whiskers (a collective headgear trait) can be inherited.
Once a My Tama is born and the user begins to care for them, they are prompted to give them a name. All My Tamas have a "-tchi" (っち) suffix at the end of their name. On Japanese releases, the Tamagotchi will automatically generate a name based on what parents the baby had, although the user is free to change it from there. For English releases, all My Tamas start with an empty name field that must be filled in.
The baby stage for the My Tama will closely resemble the standard baby of that Tamagotchi version, allowing the user to know the gender of the baby immediately. A headgear trait will emerge at the child stage, an accessory trait will emerge at the teen stage, and the body trait will emerge as an adult. In rare cases, the headgear and accessory traits may completely change upon reaching the adult stage. On the Tamagotchi On, twin My Tamas may either grow to be completely identical, or have different genetic traits emerge by the adult stage. If a My Tama dies, all of the genetic traits are lost when the next egg is hatched.
The body parts expected to be inherited by the offspring is already determined when the baby is born and cannot be influenced by the user in any way. While it is possible to make certain traits more likely by marrying the same Tamagotchi characters repeatedly over several generations, no trait is guaranteed. When connecting two Tamagotchis on the Tamagotchi m!x, the two Tamagotchis can get a prediction from Gypsytchi about what their children will look like. The prediction is not guaranteed; it is a "best case" scenario that is most likely to happen if the resulting child is given good to perfect care.