Gudetama is a fictional character created by Sanrio designer Emi Nagashima, known by the pen name Amy, and first appeared in 2013. The name is a portmanteau of the Japanese words gudegude, meaning lazy or lacking energy, and tamago, meaning egg, which together translate to lazy egg. The character was inspired by a droopy egg yolk Nagashima observed while preparing dinner after a long workday, which she felt resembled the tired demeanor of modern young people. Gudetama is an anthropomorphic egg yolk, typically depicted as a yellow yolk with a prominent cleft, a head with no neck, a body with small limbs but no fingers or toes, lazy oval-shaped eyes, and a mouth with a tongue but no visible teeth. It is often shown lying on an egg white as a bed, sometimes using a strip of bacon as a blanket. Soy sauce is its favorite food and is one of the few things that can spark a glimmer of motivation in the character.

In terms of personality, Gudetama is defined by its perpetual apathy, lethargy, and pessimistic outlook. It embodies a state of being tired of life, often complaining about its existence and showing little determination or interest in the world around it. Unlike many other cute characters, Gudetama falls into the kimo-kawaii, or gross-cute, category due to its depressive and sardonic nature. It is sarcastic, often rude to other characters, and seems to have a passive acceptance of its fate as a food item, expressing a desire to simply wait to be eaten. This attitude serves as a humorous reflection of societal disenchantment and burnout, particularly among millennials, making the character relatable for expressing feelings of exhaustion and lack of motivation.

Within the narrative of the Netflix series Gudetama: An Eggcellent Adventure, Gudetama's primary motivation is not a typical goal but rather a resigned willingness to simply exist and eventually be consumed. The story begins when it hatches from a blue egg laid by a hen named Hana. Gudetama is reluctantly pulled into a journey across Japan to find their mother, though its own motivation remains low throughout most of the quest. Its role in the story is largely as a reluctant participant, contrasting sharply with the energetic and determined personality of its traveling companion. The character's development across the series is subtle but significant. Starting from a place of complete apathy and a wish to be eaten, Gudetama is gradually influenced by the persistence and optimism of its friend. While it retains its core laziness, the journey forces it to engage with the world, and by the end, it faces a bittersweet acceptance of its fate as an egg, showing a glimmer of growth and connection.

Key relationships are central to Gudetama's story. The most important is with Shakipiyo, a lively and hyperactive chick who wears an eggshell as pants. Shakipiyo's relentless energy and determination to find their mother often pester and annoy the lethargic Gudetama, but the two form an unlikely and deep friendship as they travel together. Other notable egg characters include Hardboiled, a jaded and menacing egg cooked for over fifteen minutes, and Guretama, a spoiled, greyish egg with an irritated expression who is even grumpier and more aggressive than Gudetama.

Regarding notable abilities, Gudetama possesses a few unique traits despite its lazy demeanor. It can use its chalaza, the bands of tissue that anchor the yolk in a real egg, as a lasso or a weapon by throwing it. Additionally, the character appears in various forms corresponding to different cooking methods, and despite being repeatedly sliced, cracked, cooked, and eaten in its various animated shorts, it is consistently reincarnated or returns as a new, unbroken egg in subsequent episodes. The character also has the ability to shapeshift, being an obake, a type of spirit or yokai that can change its form. This ability is reflected in the many different depictions of Gudetama, from a raw egg to various cooked dishes.