Killer B's Jinchūriki Forms

Kirābī is a Jinchūriki of the Eight-Tailed Beast, and is therefore capable of transforming into various forms that resembles his Tailed Beast, until he finally takes on the complete form of his Eight-Tailed Beast. So far, he has only displayed two forms. Unlike Naruto and Gaara he seems to have full control of his Tailed Beast and his transformations.

Three-Tailed Transformation
When need be, Kirābī will tap into the Eight-Tailed Beast’s chakra and generate a demon cloak similar in appearance to Naruto’s One-Tailed Transformation (and onwards).

In this form will his incisors grow long and sharp and Kirābī is covered in a boiling chakra shield, that takes the shape of his tailed beast by forming three tentacle-like tails on his behind, and paws of chakra around his hand. However, instead of just creating ears like the demon fox's cloak, his chakra cloak has formed what appear to be a pair of bull-like horns. Due to Kirābī's great control of his Tailed Beast, this transformation can be done instantly.

In this form, he becomes powerful enough to blow away Sasuke's entire neck and chest, but also begins to move in a straight line, something Sasuke noted to be a weakness. However, Kirābī simply retorted that Sasuke would not be able to keep up. According to Kirābī, only Sasuke and his own brother could match up to his speed.

Full Transformation
While fighting Sasuke Uchiha and his team, Kirābī managed to wound Sasuke long enough to transform into a full form.

In this form, he takes on the appearance of the Eight-Tailed Beast itself, rather than just a cloak, appearing like a huge ox with eight octopus-like tentacles as its tails and four horns on his head, though with one of them broken. Like with his previous form, he seems to be in full control of this form, however to what extent is still unknown.