|Relatives:||Guhvorn, Guhlith, Guhweep|
| Spoiler warning!|
This article contains plot details about the story of a game.
Guhnash is a planet-eating monster. Every part of this monstrosity's body is a weapon, including its 3 brains: Guhlith, Guhvorn, and Guhweep. Guhnash is responsible for the disappearance and destruction of many planets, not the least of which was the home planet of the Dinaurians.
Guhnash is first mentioned near the end of the game, before it is actually revealed as the final boss. During the expedition to Secret Island, the hero and his partner Duna discover an old computer that briefly mentions the titan. The reason for the ancient spaceship's crash on Secret Island is because it was holding onto a Guhnash tissue sample, which subsequently caused the ship to malfunction. Duna then reveals that the monster is responsible for devouring her home planet, thus indirectly inspiring the idea for Project: Mother Planet.
As mentioned, the creature is not fully revealed and described until the very end of the storyline. When Raptin reactivated the main idolcomp upon the conclusion of the battle with Dynal, it finishes sending the coordinates of Earth to Guhnash (having started sending those signals when it was first activated millions of years ago, before the sub-idolcomps stopped it). Apparently, summoning Guhnash was the only way the main idolcomp could destroy all life on Earth.
Different plans are discussed about how to save as many people as possible from the monster - but all were considered futile, even the suggestion of destroying the monster. It is stressed, like on Secret Island, that no weapon can kill Guhnash. However, Dr. Diggins suggests that such an idea is not so far-fetched, saying that he was able to study the Guhnash tissue samples during his time on the crashed spaceship and determine that Guhnash could not survive without its three brains. The hero is unanimously voted to travel to Guhnash's mouth and destroy the organs in the most epic of Fossil Battles.
However, the hero must first choose someone to accompany him on the transportation device, which has been programmed with the coordinates of Guhnash's mouth. There is a choice between Duna or Rosie, and depending on who you choose, the final scenes of the storyline will be slightly different. When the choice is made and the pair is transported into the monster's mouth, the battle with Guhnash's brains quickly commences.
Once the final battle is won and the brains defeated, with nothing to regulate his energy, Guhnash explodes. The uncontrolled energy output interferes with the Dinaurians' teleportation device, which Rosie/Duna came prepared with, and thus renders the pair stranded in Guhnash's mouth. However, it turns out that they also came prepared with a portable stone-sleep device, which they can use to ride out the explosion safely. The player and Rosie/Duna hold hands and use the stone-sleep device to turn into stone before Guhnash explodes. The hero is later retrieved and "revived" in the Fossil Center.
However, the incredible energy that poured out upon Guhnash's destruction had actually also interfered with the stone-sleep devices' functionality. Depending on the choice the hero made, Rosie loses her memory in the process of being awakened from sleep; Duna, however, cannot change back from stone, even with the aid of the Dinaurians' vast technology. Suddenly, the Digadig Chieftain appears and tells the player that doing the hip-shaking dance will provide the cure. Upon doing so, the dance indeed returns Rosie's memory (or successfully revives Duna).
Post-game, you can talk to Mr. Richmond and he'll allow you to reenact this battle against the brains, all of which are at Rank 11. Also, once the time machine sidequest has been completed, you can actually use the time machine to return to the final part of the storyline, thus allowing you to redo the battle over and over again. Because the battle gives you 30 points for winning each time, it is useful for raising other Vivosaurs.
As every part of Guhnash's body is essentially a living weapon, the monster's brains are surprisingly vicious. They are Guhvorn, Guhlith, and Guhweep. In addition to being fierce enemies, their purpose is to regulate the flow of Guhnash's energy. They are all of the Legendary Element (which acts as Neutral), and therefore, they have no weaknesses and strengths overall. While they all have the same Accuracy stat of 30, the similarities end there. Guhvorn is the most offensively powerful of the trio, while Guhlith is the most defensive, and Guhweep acts as a supporter with its healing and evasion skills.