Utakata's Jinchūriki Forms

Utakata was the jinchūriki of the Six-Tails. He's capable of using the Six-Tails' chakra in various and different levels, and was able to control the power up to the sixth tail. In the past, the Six-Tails has already manifested while protecting his vessel from any harm; but because of his power, he swore to never use it again. Similar to Naruto Uzumaki, Utakata has a seal in his stomach possibly to limit the Six-Tails' power.

Initial Jinchūriki Form
By using the Six-Tails' chakra, Utakata was capable of realising his power and turn the tide of battle in his favour. In contrast to Naruto, Utakata's eyes turn yellow while displaying this power, but he doesn't have any other changes like Naruto. With this, his physical power and chakra increase considerably making it possible for him to free himself from any control such as Shiranami's Character Bind Technique. In this form, he displays waves of chakra towards many enemies and is capable of overwhelming them without any problems.

Initial Six-Tailed Form
Although Utakata doesn't use this form often, he was able to restrain the powerful kinjutsu from Hotaru with only the power of the chakra cloak. The cloak, like that of all other jinchūriki, surrounds the host and forms a number of tails made of chakra. In Utakata's case, there are six tails as well as the slugs antenna.

Version 2
While the resurrected jinchūriki where beeing sealed by B's Ink Clones, they all quickly transformed into a version 2 of their Tailed Beast forms.

Partial Transformation
While it is unknown how much control Utakata has over the Six-Tails, after his resurrection, he was able to form one of the beasts tails without the use of a chakra cloak.

Full Six-Tails Form
During the attempted forced extraction by his master of the Six-Tails from Utakata's body, Utakata slipped into his full Six-Tails form and killed his master. After this incident, Utakata defected from Kirigakure and developed his hatred for master and student relationships. It is not known, however, if Utakata was in control of his body during the transformation, or if the Six-Tails took control, similar to the Nine-Tailed Demon Fox when it takes over Naruto. But seen when Utakata tried to stop Hotaru's kinjutsu, he asks the Six-Tails to give him the power to stop it and as seen in the end, the Six-Tails didn't take control of Utakata.