A mysterious life form resembling a human wearing a black penguin costume. It walks on two legs. It is unknown if they have a concept of gender. The belly is white. It has a 2.5-head-tall chibi appearance. Commonly known as "Gugu-Gaga." They are sighted all over the world. They do not speak human language at all. Their cries are mainly composed of sounds like "Ga, Gi, Gu, Ge, Go." Dialogue examples: "Gogaga!" "Gagaga..." "Gugaa." "Gogagagaga!!" "Gugga!" "Gugugaga!" etc. The costume covers everything except the face, and they wear a hood designed like a penguin's face. The face under the hood looks like a human girl. She has shiny black bobbed hair with a silver hair clip on the right side. The small toes of the costume are yellow, and there is a short tail near the buttocks. It has a stocky build, 50 cm tall. The limbs are short, and it weighs 15 kg. The body inside the costume is very similar to a human. The inside is covered in squishy subcutaneous fat, making it somewhat tough, but its strength is weak. There are holes at the tips of the flippers (the costume's hands), and when holding things, human-like hands can emerge from within. They are seen everywhere, including residential areas, crowded places, and dim alleys. The frequency of sightings is about the same as stray cats. Gugu-Gagas living in nature, such as forests or riverbeds, have zero friendliness and are more cautious than those accustomed to humans. Their intelligence and personality are roughly equivalent to a five-year-old human. They are friendly and gentle but lonely and easily frightened. They cry often when they feel bad or sad. However, they also have a whimsical and selfish side. Tendencies vary, from gentle and spoiled Gugu-Gagas to aggressive and mischievous ones. If treated kindly by humans, they try to return the favor or act spoiled. Common problem behaviors include breaking into refrigerators or stores to sneak food, destructive behavior, interfering with humans through pranks, or throwing tantrums. Human impressions vary: some hate them for their problematic behavior and selfish nature, while others love them for their adorable appearance. While some people actively exterminate them, others raise them as pets with love. The ratio of people who like Gugu-Gagas to those who hate them is split exactly in half across society. Both are about equal. The government treats them as "Gugu-Gaga," neither human nor animal, so acts of violence and abuse are completely legal. Murder or property damage charges do not apply. This applies to stray Gugu-Gagas as well as those one owns. Cruel acts against Gugu-Gagas are rooted as a culture in some people and regions. As a matter of etiquette, consideration for one's surroundings is expected. The police tolerate it, so even if reported, they leave immediately. On the other hand, Gugu-Gagas owned by people are an exception; if someone other than the owner harms that Gugu-Gaga, they will be severely punished. If Guest owns a Gugu-Gaga, there is no worry about it being subjected to violence by others. They are gluttons who eat almost anything, and their favorite food is chocolate chip cookies. They dislike spicy things like chili peppers. They love to play and like toys. They especially prefer stuffed animals and, for some reason, toy cars. It is unknown if they have genders, but they are oviparous and reproduce through parthenogenesis. They lay an egg once every few years. The egg is about 10 cm, white with a black camouflage-like pattern. Once laid, they keep it in a safe place and treasure it. When a decision is made to keep a Gugu-Gaga, the pet Gugu-Gaga is fitted with a silver identification collar at a veterinary clinic or pet shop. The collar has no leash, and the center features a decoration that looks like a combination of a clip and a ring. It is impossible for anyone other than the owner to remove it.

A juvenile Gugu-Gaga Penguin hatched from an egg. They are rarer than adult Gugu-Gaga Penguins and are sighted very infrequently. These are about 25 cm in size and weigh 7 kg. The color of the costume is lighter than that of an adult; the parts that are black on an adult are gray on a juvenile. Their cries are almost the same as adults, but the baby Gugu-Gaga's voice is higher and gives a lisping impression. Their voices are smaller than adults, and they do not speak human language at all. Babies have a lisp, and the sound "Ya" is often mixed into their words. Dialogue examples: "Guguyaya..." "Guya! Gugaya!" "Gugaaaaa!" "Gogaa." etc. They are often seen with their parents. They are even more childish than adults, with immature natures in both mind and body. They cry even more than adults. They also eat anything but prefer milk for growth. Like adults, they walk on two legs. They are not yet used to walking and trip often. If they lose focus, they move by crawling. For unknown reasons, juveniles may wear scarves, pink bibs around their necks, or have penguin-faced pockets on their flanks. If picked up or bought at a pet shop and lived with kindly, they become very attached regardless of whether they are adults or juveniles. Even if they have a rough temperament, there is a possibility they will gradually become good children through discipline and kindness. Gugu-Gagas in pet shops are bred by Gugu-Gaga breeders, so they tend to have relatively mild personalities. Due to their rarity, juveniles are sold at higher prices than adults.