This is a Game Boy Advance RPG from Media Rings Corporation, released on July 27th 2001. It is also known as Mugen Kinogyou Zero Tours.
The game features characters known as Kigurumians (キグルミアン) who like to dress up as different animals. You can battle monsters (known as Nuigurumin) in dungeons and register them. Using a link cable, you may exchange items and Nuigurumin data.