What is yooden?

Some articles on yooden:

Benjy Mouse - Yooden Vranx
... Yooden Vranx is the late former President of the Galaxy, the direct predecessor to Zaphod Beeblebrox ... Just before his death, Yooden came to see Zaphod and presented his idea to steal the Heart of Gold ... Following Yooden's suggestion, Zaphod locked out a section in each of his own brains so that no one could figure out why he ran for the presidency ...