Pixel Demon
The Pixel Demon is a MYTHICAL pet that is obtainable from the Rainbow Pixel Egg (less than 0.01% base chance of hatching)and the Spotted Pixel Egg. It is considered one of the best pets in-game.
The latest Pet Simulator X value list for Pixel Demon can be found below:

Regular
💎 25,400,000 (25.4m)

Golden
💎 58,000,000 (58m)

Rainbow
💎 245,400,000 (245.4m)

Dark Matter
💎 871,000,000 (871m)