Super OVA 1: Based on a story from vol. 27 of the manga, Shampoo and Ukyo arrange to travel to a cave that is legendary for breaking up couples. They hope they will cause Ranma and Akane to break-up and Shampoo hopes to ditch Mousse the same way.

Super OVA 2: "Jaaku no Oni" (lit. "The Wicked Demon") was released in 1995. Based on a story from vol. 29 of the manga, an Oni (that wears a tiger-striped diaper just like the Oni of Urusei Yatsura) escapes it's sealed box and begins to possess people in the neighborhood.

Super OVA 3: This is a story from vol. 31. Ranma disturbs a doll that takes revenge on anyone that shows it disrespect. In order to teach Ranma a lesson, the doll possesses Akane and tries on many occasions to attack him.

[Source: AniDB]