Ghost Rex, as the name implies, is a giant, robotic Tyrannosaurus Rex. It has yellow, orange and lime triangle-like patterns all over its body with lime-green spikes on its back. It has green eyes, gray robotic parts on its legs, and a blue mouth along with off white teeth. It also has a red jewel on its forehead.
The Ghost Rex's weak point is its head. It attacks by biting and ramming across the player's platform but the player can hold this off by jumping on its head. Once it has taken enough hits (usually around half of its health gauge), the Ghost Rex will stomp wildly, causing the ground to be cracked open. The fight will continue as normal, however it then takes place in the touch screen and the Ghost Rex gains a new attack in which it slams its head at the player, making it harder for the player to hit. When almost defeated, the Ghost Rex will lay its head out ready for the player to deal the final blow on it but if left on this state for too long, the Ghost Rex will regenerate some health and the fight continues.
In normal mode, the Ghost Rex gives the player less time to damage as much as possible. Sometimes when biting, the Ghost Rex will bite at the area three times consecutively before it is left vulnerable for the player to attack.