Ryo-Ohki (魎皇鬼 Ryō'ōki; sometimes written Ryo-Oh-Ki) is a character in the Japanese anime series Tenchi Muyo! and its spinoffs. Ryo-Ohki's appearance is similar to a cross between a cat and a rabbit, and for this reason Ryo-Ohki is commonly referred to as a cabbit. Ryo-Ohki also served the role of mascot for Pioneer Entertainment before that division of Pioneer Corporation became Geneon. Ryo-Ohki's name means "dragon king", although some translations come out to the more fitting "something small that has the potential to be big."

Ryo-Ohki's appearance as a cabbit, love of eating carrots, and association with the character Sasami are common among all of the series in which Ryo-Ohki appears. Ryo-Ohki is usually a shapechanger, but the shapes, aside from the cabbit form, vary according to the series. Ryo-Ohki's background and other traits very considerably from one series to another.

• In the Tenchi Muyo! Ryo-Ohki original animated video (OAV) series, Ryo-Ohki is a unique artificial life-form created by Washuu. She is initially Ryouko's companion. She and Sasami quickly become attached to each other, however, and she generally chooses to spend her time with Sasami rather than Ryouko. She possesses the ability to transform herself into a spacecraft. Following an incident later in the series, she gains the ability to shift to two catgirl-like humanoid forms — a child form and an adult form.

• In the Tenchi Universe continuity, Ryo-Ohki is not unique; another cabbit, named Ken-Ohki, appears in the series. Her origins are not known. She is otherwise similar to her OAV incarnation, serving as Ryouko's companion and spaceship and Sasami's pet.

• In Tenchi in Tokyo, Ryo-Ohki is Sasami's pet. She transforms into a gigantic pink-colored mecha.

• In the Pretty Sammy OAV series, Ryo-Ohki can speak. He(Ryo-Ohki is male in the Pretty Sammy series') serves as an advisor to Sasami, who becomes the magical girl Pretty Sammy. This relationship is a reference to the magical-girl genre convention of the animal advisor; it was most likely meant as a parody of the relationship between Sailor Moon and her cat Luna.

• In the Pretty Sammy television series (also known as Magical Project S), Ryo-Ohki is a boy from the magical dimension of Juraihelm, who takes the shape of a cabbit in order to serve as Sasami's advisor. Like the OAV version, he speaks while in cabbit form.