Hysalrians were considered strange-looking, and featured serpentine lower halves. Their upper halves were vaguely more humanoid, although they featured four arms. Their heads featured a small mouth, and four eyes, which were small and black. The skin of the Hysalrian was a muted green, and their underbellies were white and segmented.
The Hysalrians were native to a swamp planet, as well as the Hysalria system. One Hysalrian, N'Kata Del Gormo, lived on the swamp planet, and was a Force-sensitive. When two other Force-sensitives, Yoda and a Human, crashed on the planet, Del Gormo trained them in the ways of the Force. Yoda and the Human were later rescued by ships from the Galactic Republic. Yoda went on to become the Grand Master of the Jedi Order.
The Hysalrians were created by Chuck Hamilton, a 23-year-old Star Wars fan, through the "Design An Alien" competition, which was run by Star Wars Galaxy Magazine. The competition, which was launched in Star Wars Galaxy Magazine 3 (1995), called for readers to conjure up entirely new alien species based on what had been shown in the original trilogy of Star Wars films. Hamilton's entry was not included in the winners showcased in Star Wars Galaxy Magazine 7 (1996), but was later printed in the "honorable mentions" section in Star Wars Galaxy Magazine 9 (1996).
Holocron continuity database keeper Leland Chee has stated that the published "Design an Alien" material is considered canon unless contradicted by another source. Hamilton's original entry stated that the Hysalrians were native to Dagobah, and that N'Kata Del Gormo had trained Yoda there. This was later contradicted when Chee stated that, per the Star Wars Episode III: Revenge of the Sith novel (2005), Yoda's trip to Dagobah in 19 BBY was his first ever trip there, which would have occurred long after his original training. Chee did state, however, that the character of N'Kata Del Gormo did still exist in canon. As such, an unidentified swamp world is substituted for Dagobah for the purposes of this article. The Essential Atlas (2009) furthermore established a "Hysalria," as a homeworld for the Hysalrians, but no explicit connection has been made between the swamp world and Hysalria. Author Jason Fry did, however, place Hysalria close to Dagobah to solidify the connection, and also intended to imply a connection between the Hysalrians and the Sluissi.