Nyan Cat
The Nyan Cat is an EXCLUSIVE pet that was only obtainable from the Exclusive Shop. It was released in the Tech Update. It is based on the famous Nyan Cat meme.
The latest Pet Simulator X value list for Nyan Cat can be found below:

Regular
💎 58,000,000,000 (58b)

Golden
💎 Not Available

Rainbow
💎 Not Available

Dark Matter
💎 Not Available