Ruby WEAPON
Ruby WEAPON appears once Ultimate WEAPON has been destroyed. You'll find it peaking out of the sand surrounding the Gold Saucer. To initiate combat fly into thes head and it will surface.
Unless the WEAPON's claws are buried in the sand, its torso is invulnerable. Attacking it at such a time will prompt Ruby WEAPON to use its quicksand attack that instantly eliminates a member of the party. Typically Ruby WEAPON will use this attack twice, cutting your party down to one. This, of course, makes the battle a lot tougher. Once Ruby WEAPON buries its claws, attack the torso at full force-Quad Magic and Bahumat ZERO works pretty well, but Kinghts of the Round typically prompts Ruby WEAPON to retaliate with Ultima. Be sure you equip your characters with the Final Attack - Revive combination or you won't stand a chance.
For winning the battle you receive the Desert Rose. It may not seem like must at first, but it can be traded in at Kalm for a cool prize (check the Kalm Traveler section).