This article is incomplete. Please feel free to edit this article to add missing information and complete it. Reason: Updating History section with USUM information, adding level-up movepool comparisons
Artwork drawn by Hitoshi Ariga depicting the first Ultra Beasts to appear in the series
The Ultra Beasts (Japanese: ウルトラビーストUltra Beast) are a group of extradimensional Pokémon originating from Ultra Space. They possess power that transcends humans' understanding of the world.
Ultra Beasts infrequently appear from Ultra Wormholes in Alola. These appearances are apparently as unexpected for the Ultra Beasts as for Alolans, which tends to make them combative. They are especially drawn to people who have passed through an Ultra Wormhole, due to the residual wormhole energy on them, apparently expecting to find a wormhole they can use to return home.
When encountered in the wild, the residual energy from Ultra Wormholes manifests as a red aura that boosts one of their stats at the start of battle, similar to a Totem Pokémon's orange aura. Wicke theorizes that they store this energy in their bodies.
Most Poké Balls have difficulty recognizing Ultra Beasts as Pokémon due to their extradimensional origins, impairing their ability to effectively catch them. Only the Master Ball and Beast Balls escape this impairment.
Although unconfirmed, Aether Foundation scientists hypothesized that Cosmog is also an Ultra Beast, due to its ability to create Ultra Wormholes. Necrozma's Pokédex entry also states that it is "reminiscent of the Ultra Beasts", but when it was in the wild, the International Police reported that all Ultra Beasts it had detected had been caught, and Beast Balls are not effective at catching it. Additionally, Dulse refers to Necrozma as "a creature almost like an Ultra Beast" in Pokémon Ultra Sun. In the anime, the Aether Foundation, mistaking Necrozma for an Ultra Beast, gives it the codename "UB Black".
Although an extremely rare event, legends in Alola tell of fearsome Pokémon appearing from Ultra Wormholes. The legends also tell that the guardian deities would fight fiercely against them.
The Aether Foundation also conducted research on the Ultra Beasts. This included the development of the Beast Killer project to create a Pokémon—Type: Full—that could fight against Ultra Beasts. The Beast Killer project ended in failure, and the three known Type: Full were cryogenically frozen and their names changed to Type: Null. It also developed the Beast Ball to catch the Ultra Beasts.
The International Police have also tracked Ultra Beasts in the past and into the present under a secret division known as the UB Task Force. The UB Task Force is tasked with investigating the ecology of Ultra Beasts, protecting people from harm from them, and either safeguarding or destroying the Ultra Beasts. Ten years prior to the events of Sun and Moon, a three-person team composed of Looker, Nanu, and an unnamed Faller came to Alola to track down and destroy a Guzzlord; in the process, the Faller was killed. The International Police refer to each of the Ultra Beasts by code names.
The first reported sightings of Buzzwole, Pheromosa, Xurkitree, Kartana, and Celesteela were after the incident at Aether Paradise where Lusamine forced Cosmog to create an Ultra Wormhole and used it to travel to Ultra Space.
During the main story, the player encounters Nihilego at Aether Paradise during their first meeting with Aether President Lusamine, when it emerges from a spontaneously appearing Ultra Wormhole. During the player's confrontation with Lusamine after she captures Nebby, Lusamine uses Nebby's power to open Ultra Wormholes across the Alola region, bringing Ultra Beasts into the region; Nihilego is seen emerging from the portal near Lusamine, while BuzzwoleS/PheromosaM is seen emerging from a portal over Melemele Island and battling Tapu Koko. The player also encounters several Nihilego in Ultra Space after arriving with SolgaleoS/LunalaM and Lillie.
After the player becomes Champion, some Ultra Beasts remain at large around Alola. The player receives a card from a stranger directing them to visit the motel on Akala Island's Route 8. When they enter the guest room, they will find Looker and Anabel, who invite the player to join the International Police's UB Task Force and protect the Ultra Beasts currently loose in Alola. Upon accepting, the player begins a series of missions to capture the Ultra Beasts, spanning all four of Alola's islands, each time based out of the island's motel (or the restaurant on Poni Island). In some missions, there are multiple of the same species of Ultra Beast to be captured, and in some missions they may be found at either of two locations. If the player flees from or defeats an Ultra Beast, it remains in the area and the player will still be able to find it again immediately (either at the same place or at the alternate location, if applicable). When the player is in an area where there are Ultra Beasts during a mission, the music changes from the area's normal score.
All Poké Balls except Master Balls and Beast Balls have a catch rate multiplier of 0.1× against Ultra Beasts; the Beast Ball has a catch rate multiplier of 5× for Ultra Beasts. If a Beast Ball is used against any other type of Pokémon, its catch rate multiplier is 0.1×.
Unlike regular Pokémon, the Pokédex will not record Ultra Beasts as seen; it will only register them when they are caught. If an Ultra Beast is not in the Pokédex, its name will show as ??? in battle.
Unlike regular Pokémon, the Pokédex will not normally record Ultra Beasts as seen; it will only register them when they are caught. If a wild Ultra Beast is not in the Pokédex, its name will show as ??? in battle. However, Ultra Beasts used by other Trainers will display their names in battle and register in the Pokédex; specifically, this occurs for the Poipole used by the Ultra Recon Squad and the Kartana used by the Ultra Forest KartenvoyUS. Additionally, the wild BlacephalonUS/StakatakaUM encountered in Poni Grove do display their names and are registered in the Pokédex as seen even before the player catches them.
Moves in bold are STAB. Moves in italics do no damage. Moves in bold italics is STAB for Poipole when it evolves.
In the anime
Nihilego debuted in a flashback in A Masked Warning!, where Gladion revealed to Ash that Lillie was once attacked by one when she was younger, resulting in her present-day fear of touching Pokémon. It appeared again in another flashback in Mission: Total Recall!.
In Faba's Revenge!, Faba managed to summon another Nihilego from an Ultra Wormhole. Lusamine, Gladion, and Ash briefly battled the Ultra Beast before it took Lusamine into the Ultra Wormhole and disappeared. They were given the proper name Nihilego in The Professors' New Adventure!.
Nihilego appeared again in a flashback, and Poipole debuted in The Professors' New Adventure!. It would eventually be caught by Ash in Love at First Twirl!.
Celesteela debuted in Rise and Shine, Starship!, where Sophocles found one while camping at Bamboo Hill. He and his classmates dug it out of the ground, and although the Ultra Guardians failed to catch it due to the fact that it was rooted down, it eventually flew off back into space. Unlike other Ultra Beasts, this Celesteela had been growing in Alola for more than 200 years.
Twirling with a Bang! saw the debut of both Blacephalon and Xurkitree. Ash and his classmates first encountered Blacephalon performing during a fireworks show, thinking that it was a part of the show. The next day, they learned that it was an Ultra Beast and set out as the Ultra Guardians to capture it. However, instead of Blacephalon, they encountered a different Ultra Beast, Xurkitree. After preventing Xurkitree from feeding on electricity from a power line, the Blacephalon from the night before appeared. The two Ultra Beasts ended up in a performance showdown, each trying to outperform the other with their moves. Thanks to a distraction from the Ultra Guardians, they were able to distract, weaken, and subsequently catch the two Ultra Beasts, allowing them to be returned home.
Stakataka debuted in The Long Vault Home!, where it arrived at the Pokémon School during midnight. After several unsuccessful attempts, it later moved to another location where it was mistaken for a pedestal for Viren's statue. The statue being placed on top of it caused it to go berserk, necessitating intervention by the Ultra Guardians.
In the anime, Nebby was speculated to be an Ultra Beast by the Aether Foundation before its relationship to the Legendary PokémonSolgaleo was fully understood. Similarly, Necrozma, having not yet been identified as the "Blinding One" of Alolan myth, was given the codename UB Black (Japanese: ＵＢ:ＢＬＡＣＫUB: Black).
In the manga
In the Pokémon Adventures manga
The Ultra Beasts debuted in the Sun, Moon, Ultra Sun & Ultra Moon arc. They were first mentioned in PASM07 by Gladion, who, after losing to Sun at an Iki Town festival tournament, contemplated losing his chance to meet with the Guardian deities and instead decided to train elsewhere to prepare to confront the Ultra Beasts when they arrive.
Later, Guzma was confronted by the Kiawe, Mallow, Lana, Acerola, Ilima, and Hau, who had traveled to Po Town to talk with the Team Skull boss. Guzma instead sent a Pheromosa, Celesteela, and Guzzlord to attack the Captains' group. After the beasts proceeded to defeat the Captains' Pokémon, Guzma used a Cosmog to open more Ultra Wormholes, summoning a Xurkitree and a Nihilego. The Captains were rescued by Gladion, who used his Type: Null to battle the beasts, and managed to easily hold them back due to being created specifically to combat them.
Afterward, Nihilego captured Guzma and dragged him into an Ultra Wormhole with it. The other beasts escaped from Po Town's barrier, allowing them to wreak havoc on the rest of Ula'ula Island. Anabel and Looker arrived shortly thereafter, and while Looker went off to investigate the Ultra Beasts that broke through the walls, Anabel assisted Sun and Moon in battling a Blacephalon. Anabel attempted to capture Blacephalon, only to discover that ordinary Poké Balls do not work on Ultra Beasts. Before Blacephalon could retaliate with Mind Blown, Tapu Bulu blew it away. Afterward, while Sun, Moon, Professor Kukui, and Professor Burnet gave Tapu Bulu a Mirage Berry, Anabel speculated that there was a certain person hiding in Alola, who was capable of creating Poké Balls that would be able to capture Ultra Beasts.
In the TCG
This section is incomplete. Please feel free to edit this section to add missing information and complete it.
Ultra Beasts were introduced to the Pokémon Trading Card Game in the Crimson Invasion expansion as a classification of Pokémon cards. Certain attacks, Abilities, Trainer cards, and Special Energy cards interact specifically with Ultra Beast cards. Unlike the core series of games, the TCG considers Dusk Mane Necrozma, Dawn Wings Necrozma, and Ultra Necrozma to be Ultra Beasts. Every Ultra Beast card has an attack or Ability that affects or is affected by the player or opponent's Prize cards. In the case of an Ultra Beast GX card, this is always its GX attack. Several of the Ultra Beast-related Trainer cards interact with Prize cards as well. This association with Prize cards may be a reference to the Ultra Beasts' AbilityBeast Boost in the core series, as both Beast Boost and Prize cards center around knocking out the opponent's Pokémon.
Ultra Beast cards are distinguished by a red Ultra Beast label superimposed on the card art below the HP and type. Ultra Beast GX cards have a red graphic instead of the blue graphic depicted on other other Pokémon-GX cards. Additionally, the GX attack bar, effect text, Pokémon-GX rule box, and outlines for the Full Art graphics are colored red rather than blue. This red motif may be a reference to the red aura surrounding wild Ultra Beasts in the core series of games.
Trivia
The base stats of the Ultra Beasts, and the levels at which they learn moves (except level 1) are all prime numbers. They share this trait with Cosmog and its evolutions. The only exception is Naganadel, which has a Speed stat of 121, which is a prime power.
All Ultra Beasts except Poipole and Naganadel have a base stat total of 570.
The Ultra Beasts and the light trio (plus their pre-evolutions Cosmog and Cosmoem) all share a unique sound frequency found within or after their cries, approximately 1.250 seconds in duration. This may reflect their connection to and natural origin from Ultra Space.
The only Ultra Beasts that are part of an evolutionary line are Poipole and Naganadel.
Although the Ultra Beasts are not Legendary,[1][2] they share some characteristics with numerous Legendary Pokémon: they all are genderless, are in the Undiscovered egg group, are scripted encounters, have special battle music, are guaranteed to have at least three IVs of 31, and have special Rotom Pokédex pages.
If the player chooses to filter out people seeking Mythical or Legendary Pokémon on the Global Trade System, then people seeking Ultra Beasts will not be displayed.
Buzzwole, Xurkitree, and Guzzlord's Ultra Sun Pokédex entries; and Pheromosa, Celesteela, and Kartana's Ultra Moon Pokédex entries have exactly the same text. They are the only Pokémon with Pokédex entries identical to another Pokémon. The Pokédex entry reads as: "Although it's alien to this world and a danger here, it's apparently a common organism in the world where it normally lives."
graphic instead of the blue 
graphic depicted on other other Pokémon-GX cards. Additionally, the GX attack bar, effect text, Pokémon-GX rule box, and outlines for the Full Art graphics are colored red rather than blue. This red motif may be a reference to the red aura surrounding wild Ultra Beasts in the core series of games.
