Axolotuus
The Axolotuus is a RARE pet that is obtainable from the Shiny Axolotl Egg, with a 2% chance of hatching. It is considered the best Rare pet in the game.
The latest Pet Simulator X value list for Axolotuus can be found below:

Regular
💎 252,000 (252k)

Golden
💎 732,000 (732k)

Rainbow
💎 2,250,000 (2.25m)

Dark Matter
💎 7,000,000 (7m)