Gabumon X is described as looking similar to a regular Gabumon, but except that is more canine in appearance. It also has darker tone of blue on its pelt. On its left paw is a massive claw that is uses in attacks.
He and Agumon X starts of the story getting chased by a herd of Mammothmon, they then enter the cave of KoKabuterimon X, a Boarmon enters, and the caves shakes, and they are teleported into the Human World. They meet KoKabuterimon X's Human Friend, Dave. His friends enter the room, and they introduce themselves. The Digimon then cause a reaction with the DigiDestined's Phones, and they gain a new app.
The name "Gabumon X" refers only to the Rookie form of this Digimon. Throughout the series, Gabumon X gains the ability to digivolve into a number of more powerful forms, each with a different name and special attack. However, the Rookie level is his preferred one and the one he spends most of his time in.
Garurumon X is the Digivolved form of Gabumon X, and is described as a quadpedal form of Gabumon X. The fur pelt it once wore has now changed to cover its entire body, and has been filled with Ghostly Energy which lets its pass trough walls, and become invisible.
WereGarurumon X is the Digivolved form of Garurumon, and where Garurumon was intangible, WereGarurumon is tangible. As Garurumon's Ghost Powers were to unpredictable and uncontrolable, when it Digivolved the energy filed into the wings on its back.