Never in the history of Pokemon has New Pokemon ever been added to a given Generation for a game to its sequel; however, that will change with Pokemon Ultra Sun & Ultra Moon. That's right! For the first time ever, new Pokemon will be added within the same generation! And Pokemon Ultra Sun & Ultra Moon will begin this new trend with three brand new Ultra Beasts, ones with the Ultra Beast Code Names of UB Burst, UB Assembly and UB Adhesive.
UB Burst, the colorful creature, will be exclusively found in Pokemon Ultra Sun, and it will be a Fire / Ghost Type Pokemon. UB Burst will also have a new pure Fire Type Attack called Mind Blown, causing massive damage to the opponent, but one will a huge recoil damage as well. UB Burst has the species name of Blacephalon, having a Base Stat Total of 570 with a 53/127/53/151/79/107 Stat Spread.
UB Assembly, the towering Rock / Steel Type block structure, will only be found in Pokemon Ultra Moon. It has the name of Stakataka, having a Base State Total of 570 with a 61/131/211/53/101/13 Stat Spread.
UB Adhesive will be available in both Pokemon Ultra Sun and Ultra Moon, and it's a pure Poison Type Pokemon. UB Adhesive has the name of Poipole, having a Base Stat Total of 420 with a 67/73/67/73/67/73 Stat Spread.
In the later Datamine of both games prior to their release, it was discovered that there will actually be a fourth new Ultra Beast with the name of Naganadel (shown directly above). Naganadel is a dual Poison/Dragon Type Pokemon, and Poipole actually evolves into Naganadel by learning Dragon Pulse. Naganadel has a 540 Base Stat Total with a 73/73/73/127/73/121 Stat Spread.