Mister Treasure is the yukkuri equivalent of a human toy, and as such denotes items owned by koyukkuris, and used in their childish games. In stories, "Mister Treasure" mostly appears in its slurred form of "Mishter Threashure", as a koyukkuri could say it.
Much like human child would antropomorphize and speak with its favourite toys, is not uncommon for a koyukkuri, especially a lonely one, speak with its "Mishter Treashure" as it were its best confidant. Also, koyukkuris may argue for the possession of a particularly prized "treasure".
Much as adult Yukkuri define their "easiness" by their beauty and material possessions, a koyukkuri may feel easier with a nicer "Mister Treasure". As such, in the wild a benevolent parent will be more than willing to allow a ko bringing its improvised toys in its den, and in captivity a good owner should always buy some toys for its pet koyukkuri.
In the wildEdit
While adult Yukkuris go hunting for food, koyukkuris are often allowed, and even encouraged to follow them as soon as they're able to move, to exercise their bodies. As such, while still unable to pick up large quantities of food, they may pick up small, non-edible stuff to play with.
In nature the "treasures" available are scarce and simple, yet enough to mesmerize the attention of the still naive and guillible koyukkuris. Small pebbles, little rocks, even lost coins dropped by a careless hiker, as koyukkuris are attracted by shiny, precious-looking things ("Mister Shiny Shiny").
Alices, as a part of their "City-Sect coordination" abilities have the ability to effortlessly build some higher quality Mister Treasures, such as dolls made of straw and leaves and crude toys, very well received by koyukkuris. An Arisukkuri is thought to be ready to be an adult and earn the right to build its family when it's able to build high quality toys for its offspring. Though this practice isn't apparently practiced much anymore.
A koyukkuri or a litter of koyukkuris will always try to drag a new "Mishter Treashure" in their den, making it part of their games.
Gutter Trash Koykkuris will often play with discarded human and yukkuri toys (see below), or other small items available in the trash, as slivers of aluminium foil to "decorate" themselves, bottle caps and small tins and so on. Due to their lack of understanding about human property and activities, they may believe that "Mister Treasures grow up easy" from the trashcans on their own.
While a pet koyukkuri may still enjoy, even if it was taken from the wild, the simple "treasures" available in nature or in the trash, the resources of the average Anon allow them for more meaningful, nicer "Mishter Threashures".
Most pet shops have in stock several miniature version of the items held by the human versions of the most commonly sold koyukkuris. As such koreimus will be attracted by miniature onusas, komarisas by miniature, fake hakkero reactors and small mushrooms, and kopatchoulis by small books and grimoires. Those preferences seem to be dictated by instinct alone as it's unlikely that a wild koyukkuri may obtain or afford man-made items, yet, when in captivity, it seems to desire and enjoy them as "easier" than pebbles and rocks. As a rule of thumb, koyukkuris seems to retain, along with the general Yukkuri genetic memory, a very faint echo of the Gensokyo human character they resemble. So a koreimu will always be attracted by slightly elevated places (a "Mishter Shrine") and toys resembling the items and trappings of a Miko, and a kopatche, even if illiterate, will always seek books and notepads for its "Great Library".
Another kind of "Mishter Threasure" loved by Koyukkuris are small bouncy ball that allow them to exercise and play with. On a much deeper level of sophistication there are yukkuri Dolls, reproductions of koyukkuris of every species known. When faced with a koyukkuri doll, a koyukkuri will act much like a human child with her new doll, playing "myamya" or "big shishter" to it, munching some food in front of the doll and pretending it's eating, keeping it clean and endlessly chatting with it. Especially really young koyukkuris will act with their dolls with no difference from the way they would act to a living koyukkuri, even identifying the doll as the real article. As such, koyukkuri dolls are sought after by people able to afford and care for a single koyukkuri only, as they prevent the onset of depression and anti-yukkuritis that comes with loneliness.
Koyukkuri dolls may range from simple, painted reproduction of koyukkuri, often made of soft plastic and eraser gum, to more advanced plush dolls with recorded, pre-set phrases (such as "Chake id eajy!" and "Wet's do wub wub!").
While not commonly seen, adult yukkuri have been seen playing with "Mister Treasures". While not known why some adult yukkuri retain this behavior, it has been guessed that it could be a way for a "richer" yukkuri to show off to others. Another theory is that if a yukkuri does not develop properly during its youth it will, rather then be around other yukkuri, contain itself with inanimate objects.