Huge Cupcake
The Huge Cupcake is an EXCLUSIVE pet that is only obtainable from Gift Rewards. It was released in the Mastery Update. It is the easiest Huge pet to get and is not a limited-time-only pet.
The latest Pet Simulator X value list for Huge Cupcake can be found below:

Regular
💎 170,000,000,000 (170b)

Golden
💎 447,000,000,000 (447b)

Rainbow
💎 528,000,000,000 (528b)

Dark Matter
💎 Not Available