USApyon wears a yellow spacesuit that has rabbit-like ears on the hood, and he carries a small orange ray gun modeled after a carrot. He also has a blue jet pack attached to his back. USApyon has another mode known as Vader Mode (Japanese: ベイダーモード,Beidā Mōdo) where a glass plate flips over his face, black smoke fills his helmet, and his eyes turn red. In the anime, he presses and holds both gray buttons on the cheek area on his helmet.
While in Vader Mode, USApyon typically shoots at the target of his anger, usually Inaho. When his rage is at its peak, he transforms into in Emperor Mode (Japanese: エンペラーモード,Enperā Mōdo), where he gains pink armor and a teal-green cape. His Vader Mode-like eyes are also noticably thicker and gain a eyelash-like spike. USApyon's gun has also changed colors to reflect Emperor Mode. To activate Emperor Mode, he press and holds the buttons in front of his "rabbit ears".
USApyon uses a laser gun offically referred to as the "rabbit shot" (his exclusive item's name) and he shoots a big blue beam in the games, while in Vader Mode he shoots mulitple red beams which appear to made of electricity since in one episode when he shoots Inaho's chair it gets zapped and its "skeleton" can be seen. USApyon appears to be very strong, since even strong Yo-kai like Robonyan F and Sproink run from it. However, as Sgt. Burly states in Busters, he's a far-away attacker that is dependent on attacking from afar, and is nearly useless up close in battle. USApyon can activate Emperor mode, and when he does, he gains the ablity to fly and has a more powerful beam.
USApyon used to be an otter that was later named "Chibi" that ended up in a rabbit farm for some unknown reason. In Corocoro comic, he was bullied by other rabbits for being different from them. One day, he was selected by NASU for the first animal into space. But when they tried to test Chibi with a rocket engine, he panicked and got electrocuted by the circuit board and the rocket exploded. In Chibi's death, USApyon was born.
USApyon can change his Elemental Technique's attribute, depending on the costume his is wearing, and were considered Rare Yo-kai. In Yo-kai Watch 3, they were later made separate Yo-kai, along with his B-USApyon costume, and stripped them of their Rare Yo-kai status, except for B-USApyon:
,Ame-futo Sutairu) changes his attribute to Fire. In Yo-kai Watch 3, American Football Style instead has a Lightning attribute. The Medallium Bio for this style states: "USApyon in an American football suit. He's gonna try physical fitness for when he goes to explore the universe."
,Doraibingu Sutairu) changes it to Lightning. In Yo-kai Watch 3, Driving Style instead has a Wind attribute. The Medallium bio for this style states: "USApyon in a race car driving costume. Apperently there's no need for good driving skills for when he goes to explore the universe."
,Marin Sutairu) changes it to Water. The Medallium bio for this style states: "USApyon dressed in a scuba diving costume. He seems to have the freedom to move around, to practice for when he goes to explore the universe."
,Miritarī Sutairu) changes it to Earth. The Medallium bio for this style states: "USApyon dressed in a costume that specializes in survival battles. For when he goes into space, he wants to polish his skills in case he lives in a tough environment."
USApyon is currently the highest-ranked Partner Yo-kai at Rank B, with Jibanyan being Rank D and Whisper at Rank C.
While USApyon was removed from the localization of Yo-kai Watch Wibble Wobble aside from the main trailer/movie, one Medal Point reward a player can get is the title of 'Pyon'.
The Final Fantasy XIV Collaboration/Kula Revolving Sushi Bar Yo-kai Watch: Wibble Wobble magnets special events spelt his name with standard spelling when he was was localized worldwide much like the other mascots.
He has a verbal tic, "Dani" though it is unknown why, as it doesn't reflect his animal species like Jibanyan's, "Nyan" or where he's from, like Komasan's "Zura" and "Monge!".
In addition to this there's a slight joke about this as Sgt. Burly recognizes his cry for help as being from him, since of the "weird speech" of "dani."
Also, in episode 146 when Phonius is telling Inaho the witness' information on what "USApyon" looks like, one of the pieces of info was "Says the mysterious 'dani'."
USApyon has a Yo-kai Pad, but it's color scheme varies depending on the media form. In the games, USApyon has a red and blue Yo-kai Pad, whereas his Yo-kai Pad in the anime has an entirely blue color scheme.