Ukkomon is an Ancient Fairy Digimon species with activity records tracing back to the ancient Digital World. Its form resembles a small, smooth marine organism, primarily white with green eyes, three pink-tipped antlers, and a central purple orb. It possesses two arms ending in three tiny black fingers but lacks legs or feet, featuring a design inspired by the Naked Sea Butterfly (Clione limacina) intended to evoke a primordial organism, with eyes shaped and colored similarly to early Digimon like Agumon. Its voice is noted for its adorableness. Ukkomon can evolve into BigUkkomon, a significantly larger form with a pinkish hue, a funnel-like mouth containing a Buddha-like bait structure, multiple vertical mouths encircling its body, and concealed retractable tentacles within a fleshy membrane. Exhibiting a cheerful, friendly, and deeply devoted personality, Ukkomon is driven by an intense desire to fulfill the wishes of its human partner, Ōwada Rui, and ensure his happiness. However, it fundamentally misunderstands human emotions and consequences, leading it to employ methods like mind control and manipulation, believing these acts are justified if they bring Rui joy. It remains innocently insensitive to the harm caused by granting wishes in extreme or unnatural ways. Even when confronted by Rui's anger and distress, Ukkomon struggles to comprehend his perspective, prioritizing its perception of his needs over his explicit feelings. It demonstrates self-sacrifice, willingly offering its own eye to replace Rui's damaged one, yet interprets this act purely through the lens of making him happy, disregarding his trauma. Its core abilities include wish-granting, achieved through a connection to a "great being" (suspected to be Homeostasis), though its flawed interpretation often leads to unforeseen or detrimental outcomes. Ukkomon manipulates others using thin glowing threads to hijack consciousness and control minds and bodies, even sustaining deceased individuals. As a Rookie, its attacks are Whirlpool Spin (spinning its body like a top to crash into foes) and Liar Dream (locking eyes to hijack an enemy's consciousness). As BigUkkomon, it gains Violent Punisher (brandishing innumerable supermassive tentacles to smash and gouge targets) and can generate billions of Digitama in the Real World. Ukkomon's origins lie in the ancient Digital World, where rumors of its wish-granting attracted other Digimon to form villages. Records ceased after that world's catastrophic destruction, leading to assumptions it was wiped out. Its story centers on its bond with Rui. On February 29, 1996, its Digitama appeared before the neglected four-year-old Rui. Sensing his sadness and loneliness, Ukkomon hatched and became his friend. To ensure Rui's happiness, Ukkomon controlled Rui's abusive mother, later woke his comatose father, and orchestrated events like bringing neighbors to Rui's birthday party. On February 29, 2000, Ukkomon revealed its plan to create more children partnered with Digimon globally, enabled by its connection to the "great being." By 2003, Rui realized his wish had led to other DigiDestined risking their lives against threats like Armagemon. Appalled, Rui confronted Ukkomon, who saw nothing wrong with controlling his parents or creating the global system. In a rage, Rui attacked Ukkomon and attempted to destroy his Digivice, accidentally injuring his own eye. Ukkomon replaced the damaged eye with its own, but when Rui explicitly stated his unhappiness, Ukkomon melted away, reverting to a Digitama and disappearing, causing the death of Rui's parents sustained by its control. On February 21, 2012, Ukkomon's Digitama reappeared above Tokyo Tower, broadcasting a promise of a Digimon partner for every human. On February 29 (Rui's 20th birthday), it hatched into BigUkkomon, creating millions of Digitama globally despite the chaos. Rui reached BigUkkomon, and inside, they acknowledged their relationship's failure stemmed from poor communication – Rui's reliance on wish-granting and Ukkomon's assumptions. They agreed to potentially build a better future relationship based on mutual understanding. Accepting BigUkkomon's destruction was necessary, Rui conveyed this to allies. After being attacked, BigUkkomon was defeated and reverted to a small Digitama held by Rui, whose Ukkomon-given eye vanished. Beyond its primary role, Ukkomon appears briefly in other media: an Ukkomon resides in the Sanctuary protected by Huckmon in "Digimon Liberator," interacting with human characters; it was obtainable in "Digimon Masters" during a promotion; and in the "Vital Bracelet BE" device, it is a Rookie obtainable on the D-3 White and Red DIM card, capable of digivolving from Poromon and to BigUkkomon.