The Grachiosaurus is a large Zoid with an open-air cockpit. Compared to other Zoids in the Zoids: Wild series, it is an XL-sized Zoid.
Two Grachiosaurus are seen in the first episodes of Zoids: Wild. One is piloted by Arashi's father, the other by Kuroame. It is mentioned that Kuroanme has never met another Grachiosaurus before. The Grachiosaurus' Wild Blast is the feature of episode 6.
Kuroame again appears in episode 37. The Grachiosaurus is used to save Team Freedom from the Four Heavenly Kings of Death Metal. However, after the Zoid is hit by Truffle's Dimepulsar, it goes rogue and joins Death Metal.
The Grachiosaurus would appear once more in episode 45. Arashi initially suspects that it's Kuroame's Zoid being used to fight his allies. However, this turns out not to be the case. It's actually his father's Zoid.
In the same episode Foiegras arrives using Kuroame's Zoid. The two Grachiosaurus fight each other. One using a Death Blast the other a Wild Blast. The power of the battle causes nearby volcanos to erupt, and both Zoids disengage from the fight.