Demon Sakura Tree

The Demon Sakura Tree, also known as the Demon Cherry Tree, is a manga only character which, after getting tired of having the name of a man and his beloved written on it, absorbed the man who wrote on it and took his beloved as a sacrifice. One night while training Kuno wrote his name along with the "pigtailed girl" onto the tree (not realizing it's history) and is absorbed into it, causing Ranma to either get Kuno out of the Tree or being sacrificed.

History
Prior to the Kuno Estate being built the Sakura Tree stood and a man wrote his name and that of his beloved onto the Tree for his amusement. Eventually the Tree grew tired of being written on and absorbed the man. It also took the girl who's name was also written on it as a sacrifice.

Cursed Cherry Tree
One night Kuno is in the garden of the Kuno Estate and begins practicing. However, Kuno instead ends up writing his name along with the "pigtailed girl" onto the Tree. As Kuno blushes to himself that even when practicing his true feelings come out, the curse of the Tree then takes effect and absorbs Kuno.

The next day Ranma hears of a Demon which speaks of wanting to date a girl with pigtails, so she goes with Akane to see whats going on. While Akane asks Ranma if this doesn't remind her of something, they hear Kuno's voice asking them to date him. It turns out, however, that Kuno has been absorbed by the Tree and now has it's body but Kuno's head still visible (the Tree is also now able to move, using it's roots as legs/feet).

Ranma is overwhelmed with surprise at this sight of Tree-Kuno carrying gifts for her. Tree-Kuno then takes the two back to his Estate and explains he's having trouble getting out of the Tree and gives Ranma and Akane a document which has been passed down the Kuno family for generations. Ranma and Akane read it and learn of the Tree's past and the curse. Ranma then inspects the trunk of the Tree and sees it says "pigtailed girl" on it, just then Tree-Kuno asks her if she'll give her life for him, to which Ranma just hits Kuno over the head.

Ranma then tries to leave, but can't as there is some sort of invisible barrier in the way. Kuno then continues to read the document which also says that the Tree will keep the sacrifice close and as such is unable to leave from below the shadow of the Tree. Kuno continues by telling Ranma that he's sorry and that she shouldn't worry. Akane then reads some more of the document as well and notes that if they go on a fun date the sacrifice won't be needed.

Nabiki, Kasumi, Soun and Genma (in his panda form) arrive and say that they'll help with a party. However, Kuno feels more like he's being put on display and isn't having fun. Kuno then decides to fall onto Ranma's lap (much to her discomfort) and says he wants to feel the pigtailed girl's strong thighs, but quickly realizes he can't feel anything while he's a Tree.

Kuno then decides there's only one thing left to do that can make him happy and that's to have the pigtailed girl kiss him. Ranma draws on Kuno's face instead and the two begin to chase each other playfully. Kuno trips and falls on top of Ranma and tries to kiss her, but Ranma sends Kuno flying into the air. Unfortunately for Ranma the curse of Sakura Tree makes it so the two have to stay close together and so Kuno lands directly on top of Ranma again, forcing her into the ground.

The pair continue their "date" with Kuno offering Ranma a petal necklace made out of the leafs of the Tree and places over Ranma's head. Ranma then puts on a "cutesy" face and asks Kuno if they aren't having a good time, to which Kuno says he isn't really and must feel the pigtailed girl's warm lips against his. This annoys Ranma who punches Tree-Kuno into the air again, which seems to anger the spirit of the Tree.

The Spirit of the Tree is angered by how the sacrifice is making a mockery of him. A strong wind blows and the Tree tells Ranma that the only way to avoid his wrath is to... kiss him. Ranma decides she's had enough and gets an axe and threatens to cut the Tree down. This frightens the Tree so it releases the now unconscious Kuno and returns to how it was before all this happened. Leaving everyone to enjoy themselves, while Ranma tries to dig a hole to put Kuno in before he comes-to.