Ultimate Summoning Beast

The creature began as something close to an oversized pupa, a bloated mass sprouting tentacles and stubby arms. Once it split from that chrysalis it grew feet and took on a more humanlike silhouette. A feeding mouth sat on its belly while tentacles occupied the spot a mouth would normally hold, and it could reshape parts of itself into whatever animal it had consumed, growing wings to take to the air among them.

Built to be the perfect answer to any ninja, the beast wielded a broad toolkit. Devouring other summons let it absorb their abilities, and it could cast genjutsu channeled through its eyes as well as ninjutsu such as a Lightning Release strike. It could whip up blades of wind sharp enough to slice open Might Guy's cheek, and true to its purpose it drained chakra, a trait it proved when Yamato tried to pin it with Wood Release.

Researchers at the facility crafted the thing to be the ultimate summon. When Honoka attempted to seal it, the creature devoured the scientists, killed her, and then began consuming the island's other summoning animals before wrapping itself in a cocoon. Much later, after Might Guy was carried off by a bird summon, his crew tracked him to the island, where Aoba Yamashiro met Honoka's ghost and read the sleeping creature's mind. The beast awoke, feasted on the trailing summons, and emerged to attack the Konoha shinobi. Guy opened the fifth of the Eight Gates to buy time, kicking it into a volcano while the summons and Honoka's spirit held it fast, and Naruto finished it by hurling a Rasenshuriken that cut it apart and dropped the halves into the lava.