Abilities
Not much is known about the Six-Tails but since it is a tailed beast, it is able to use the Tailed Beast Ball. It is also able to emit corrosive, alkali substances that are extremely dangerous on contact. In one instance it was able to burn the skin of the Eight-Tails' hand.
According to Tobi, the Six-Tails first came into being in the waning days of the Sage of the Six Paths' life; to prevent the Ten-Tails' resurgence, the Sage split up its chakra and used his Creation of All Things ability to create nine separate, monstrous constructs of living chakra, which would become known as the tailed beasts. The Six-Tails eventually fell into the possession of Kirigakure and was sealed into Utakata.
According to the anime, at some point before his appearance, Utakata's master, Harusame, tried and failed to remove the Six-Tails from within Utakata to save his student from being a living weapon for his village. Utakata, however, having not heard what his master had said to him, later came under the assumption after the incident that his master had tried to kill him. This failed removal resulted in Utakata transforming into the Six-Tails and killing Harusame.
