The Cookie Mouse is a RARE pet that was obtainable from the Gingerbread Egg, with a 3% chance of hatching. It was only available for a limited time for the 2021 Christmas Event.
The latest Pet Simulator X value list for Cookie Mouse can be found below:
💎 78,000 (78k)
💎 225,000 (225k)
💎 689,000 (689k)
💎 2,160,000 (2.16m)