Gargoyle Dragon
The Gargoyle Dragon is an EXCLUSIVE pet that was obtainable from the Exclusive Pets Egg, with a 35% chance of hatching. It was released in the Axolotl Ocean update and is no longer available. A huge version of this pet, called the Huge Gargoyle Dragon, also exists.
The latest Pet Simulator X value list for Gargoyle Dragon can be found below:

Regular
💎 2,900,000,000 (2.9b)

Golden
💎 Not Available

Rainbow
💎 Not Available

Dark Matter
💎 Not Available