Eight Headed Orochi

The Yamato no Orochi (ヤマタノオロチ) is a legendary which resides in the source of the Water of Life in the forests of Ryugenzawa. It was battled by Akane so she could get some moss to finally cure Shinnosuke from having to rely on using the Water of Life to survive.



History
At an unknown point in the ancient past, the Orochi settled in the lake which feeds the various springs and other waterholes of Ryugenzawa. Locals were apparently able to regularly subdue the creature by using a whistle made from the horn of a horned mongoose, the Orochi's natural enemy.

Over time, the Orochi's coating of the Moss of Life caused the springs of Ryugenzawa to become filled with the "Water of Life".

Plot
During the events of the Ryugenzawa arc, the Orochi shifts in its sleep and blocks off the feed of water from the central lake to Ryugenzawa's outlying springs, causing them to dry up. This was of great concern to Ryugenzawa's residents, Shinnosuke and Shinnosuke's grandfather, for without the Water of Life, Shinnosuke would die of his injuries. The two caretakers, allied with Akane Tendo and Ranma Saotome, decided to risk the Orochi's hunger and went after it where it lived, goading it from its lair with the men disguising themselves as women so that Akane, disguised as a man, could attempt to retrieve some of the more powerful Moss of Life from its body.

The battle was fierce, and although they were able to acquire the Moss of Life and heal Shinnosuke with it, all might have been lost until Akane discovered that the trinket which Shinnosuke had given her a decade ago was actually the Horned Mongoose Whistle. By blowing this whistle, she subdued the Orochi and compelled it to return to the lake. This time, it settled in a new position, restoring the flow of the Water of Life.

Appearance
The Orochi is a giant, eight-headed dragon with a very unusual physical form; the eighth and largest head actually forms its body, with the seven smaller heads positioned on the ends of smaller, long necks that emerged from the "neck" of this singular massive head. These heads move and act independently of each other, and resemble a classic "Asian" dragon, albeit one lacking horns. Overall, Orochi resembles something of a dragon-like octopus but with additional heads at the end of its neck "tentacles".

Abilities
The Orochi is a true monster of an opponent, its huge size and thick scales making it extremely hard to hurt. It is impossible to say for sure if it could even be killed, though no serious effort to injure the creature was actually made in canon.

The Orochi has a single mountainous head that also forms it body, as well as seven smaller, but still huge, heads on the ends of long necks that sprout from the back of its primary skull. It is likely that all of its vital organs are actually contained in the primary head-body; as this is usually kept buried underground or submerged underwater, opponents are unable to inflict any significant damage to the creature unless they can somehow goad the main head into surfacing.

A magical plant called the Moss of Life grows on the Orochi's body. This moss is full of powerful energies and can heal almost any wound. Even being immersed in water transmutes the water into "Water of Life", which also has substantial healing powers and can cause animals who drink it to grow into gigantic sizes.

Trivia

 * The Yamato no Orochi is a legendary dragon from Japanese mythology. Having eight heads and eight tails, it devoured maidens until the exiled storm god Susano-o used trickery to kill it. In one of its tails, he found a sword, which is now one of the Three Regalia of Japan.
 * The unique physical depiction of this Orochi bears a resemblance to a Dungeons & Dragons monster called a "Beholder".