Galaxy Fox
The Galaxy Fox is a MYTHICAL pet that is obtainable from the Planet Egg, with a less than 0.001% base chance of hatching. The Dark Matter version of this pet was one of the strongest in-game at one point.
The latest Pet Simulator X value list for Galaxy Fox can be found below:

Regular
💎 5,200,000 (5.2m)

Golden
💎 15,200,000 (15.2m)

Rainbow
💎 48,300,000 (48.3m)

Dark Matter
💎 144,100,000 (144.1m)