USApyon began as Danny, an otter (also called Chibi) living on a rabbit farm. Selected by NASU and Doctor Hugley for space experiments, he accidentally boarded a rocket during an engine test. Panicking during the incident, he perished in the explosion, transforming into a Yo-kai. He initially believed he was treated well during testing but later recalled confinement in a cage and being fed only at the scientists' discretion. This past fuels his fear of abandonment and monophobia. He appears as a rabbit-like being encased in a yellow spacesuit featuring rabbit-eared hood adornments. The suit incorporates a blue jet pack and a purple tail resembling a flame. He wields an orange ray gun modeled after a carrot, the "Bunny Blaster," firing electrical laser beams. Pressing the gray cheek buttons on his helmet activates Invader Mode: a black glass plate covers his face, smoke fills the helmet, and his eyes glow red, increasing his aggression and beam power. Activating the yellow buttons atop his helmet triggers a more potent Emperor Mode, granting red armor, a teal cape, enhanced strength, defense, and speed, plus flight capability. His personality blends serious ambition with intellectual arrogance, stemming from his rocket science expertise. He displays low frustration tolerance, often reacting with anger when contradicted or provoked, triggering Invader Mode chases and attacks. Despite this volatility, he shows fierce loyalty to trusted partners, especially Hailey Anne Thomas, attentively listening to her even during topics he finds uninteresting. His fear of solitude manifests as clinginess toward those he bonds with. He adapts his combat attributes using specialized gear, each altering his elemental affinity and Soultimate move: * Football Gear (Fire/Lightning attribute): Equips "Quarterback Sack" for enhanced physical defense. * Scuba Gear (Water attribute): Enables "Scuba Splash" for aquatic combat readiness. * Survival/GI Gear (Earth attribute): Provides "Air Support" for harsh environmental resilience. * Racing Gear (Lightning/Wind attribute): Facilitates "Road Rage" for high-speed mobility. In narratives, he partners with Hailey Anne Thomas, assisting her detective agency operations in *Yo-kai Watch 3*. This partnership leads to automatic befriending during her storyline. He reappears in *Yo-kai Watch 4*, obtainable via Quest 021 or Gutsy Bones battles, and features in spinoffs like *Yo-kai Watch Blasters* as a formidable ranged fighter and *Yo-kai Watch Busters 2*, joining Hovernyan as an automatic ally mid-game. During the events of *Sora Tobu Kujira to Double no Sekai no Daibōken da Nyan!*, he investigates the dimensional shift caused by a flying whale, reporting Hailey Anne's intensified scientific focus in the transformed world. He collaborates with Nate Adams to locate the whale, participating in search teams alongside Komasan and Shogunyan.