- "An Eborsisk, by the gods! Kill it! Forget the man! Slay the beast before it breathes!"
- —General Kael, in Willow: A Novel
During the battle of Tir Asleen, Willow Ufgood was surprised by a troll. He used Cherlindrea's wand to transform it into something else, and it resulted in a two-headed mass of flesh. He kicked it into the moat. The water started to boil, and shortly after a fully adult Eborsisk emerged, scaring both Madmartigan and the Nockmaar soldiers who were after Elora Danan.
The Eborsisk and its flames brought havoc to all parties, until Madmartigan jumped on one of its heads and impaled it with his sword. Unable to breathe fire, the head exploded, killing the creature.
According to IMDB, the name of the creature is a reference to the movie critics Roger Ebert and Gene Siskel.
Clint Howard, Ron Howard's brother, was a partial inspiration for the creature, as Ron couldn't find a cameo part for him in this movie (as in many others of his films)
It bears a little resemblance to Zmey Gorynych, a three-headed dragon from Slavic mythology and King Ghidorah from the Godzilla franchise.