Shiromari

is a chameleon summon that took the form of a castle and the personal summon of Kōza Kubisaki.

Background
Shiromari was summoned over fifty years ago by Kōza Kubisaki. As a last resort in a war, the dying lord of the castle summoned Shiromari and had it devour anyone who approached. The lord died before he could release the summoning, and thus it remained bound to the contract scroll used to summon it.

Appearance
Shiromari is a giant chameleon with huge beat red eyes. When it was released, its entire body looked like a tornado with large red eyes.

Abilities
Shiromari had the ability to shape shift and change its form completely. It was even able to take on the form of an extremely large castle. Its shape-shifting ability was so detailed and intricate, it could manipulate even the smallest details. Within the castle, it was able to mimic anything that would normally be found within one (lamps, pictures, stairs, carpet, etc.). In addition, its shape changing abilities are apparently long lasting, keeping its form for an indefinite amount of time. The chameleon, itself, was apparently large enough to devour many people.

Lady Daimyō Search Mission
During a mission to find a group of missing people, Naruto, Hinata, and Kiba stumbled upon this summon. After being swallowed by it, they realised just what it is. While attempting to find the contract scroll that was keeping it summoned, the spirit of the castle lord appeared and led them to it, because the lord felt sorry for the creature spending fifty years guarding his castle, and wanted to set it free. The summoned creature was very loyal to its summoner, having protected its summoner's castle for so long. Naruto cut the scroll into pieces to send the summoned creature back, and escaped with everyone else from the body of the summon with Rasengan. The anime does not show Shiromari's true form, but instead, a picture of what appears to be a chameleon.