In the movieEdit
Prince Valium is engaged to marry Princess Vespa of Planet Druidia. The princess has to marry a prince, and he somehow became the last prince in the galaxy. (Whether they mean the last single prince, the last living prince, the last prince Vespa had yet to reject seems unclear.) During the wedding, Vespa unshockingly gets cold feet and storms off in her luxury starship, taking her maidservant, Dot Matrix with her. While King Roland and the wedding guests are in shock about this turn of events, Prince Valium barely protests, simply saying drowsily "Wait, come back!" then yawns.
When Vespa returns to her home planet, Valium is one of the first people to welcome her back. They attend "Take Two" of their wedding, only for Vespa to realize she would rather marry Lone Starr. After Lone Starr reveals that he is a prince, and asks Vespa if she would like to marry him, she pushes Valium aside and accepts.
- Prince Valium is a play on a well known prescription sleep aid of the same name (which is why he can't seem to stay awake).
- A lesser part of the "Prince Valium" joke was a longtime comic strip called "Prince Valiant", about a prince under King Arthur who was well-known for his valiant deeds, but also having shoulder-length jet black hair in a "page boy" hairdo.
- It was later used as a joke in the film Beetlejuice, which debuted one year after Spaceballs, where Lydia tells two ghosts their attempt to scare her stepmother is fruitless as "She is sleeping with Prince Valium" tonight.