Yamata

Yamata (やまた, Yamata) is a sword that "ate" the Hebi Hebi no Mi, Model: Imoogi, and was formerly owned by an unnamed Marine, and later stolen by Gozen Tomoe, its current owner.

Appearance
When not transformed, Yamata is a normal looking wakizashi, with a red hilt, and golden guard, sheathed in a black scabbard. It is typically kept with Tomoe, tied onto her white sash, around her waist.

When transforming, the blade is the first to change, turning into a serpentine head, with a sharp, blade-like nose, steadily increasing in size and length the more it transforms, moving like a serpent would. Though, his size seems to be adjustable.

When fully transformed, Yamata is a large serpent, being the length of a giant's arm, and big enough to swallow a human whole. He possesses blank eyes, and black and white scales, in addition to spikes running across his back, and a crown-like stylized set of horns on his head.

Trivia

 * Yamata's name comes from the Yamato-no-Orochi from Japanese folklore, a giant, eight-headed, eight-tailed Dragon that was slain by Susanoo.