Domortuus
The Domortuus is a LEGENDARY pet that is available from the Dominus Egg. It first existed in Pet Simulator 1. It can be found in the Spawn World.
The latest Pet Simulator X value list for Domortuus can be found below:

Regular
💎 8,000 (8k)

Golden
💎 23,000 (23k)

Rainbow
💎 80,000 (80k)

Dark Matter
💎 No Data