Zangoose is a bipedal Pokémon resembling a cross between a mongoose and a cat. Despite being classified as a bipedal Pokémon, it usually walks on all fours. Its fur is mostly white with deep red, scar-like markings on the face, chest, and forepaws. Its fur stands up on end when it smells its arch-enemy Seviper nearby. It has two long, black claws on its forepaws, which curl underneath the forepaws when not in use, and pink paw pads on its hind feet. It has pink eyes, long ears, and a small red nose. When it opens its mouth, two sharp fangs can be seen on its upper jaw. There are small tufts of white fur on its shoulders, and it has a large, fluffy tail.
Zangoose is bitter enemies with Seviper, which it has battled for many generations. It is agile enough to easily dodge incoming threats, and it attacks foes with its sharp claws. Despite its hot-blooded and brave nature, it has been known to enjoy peaceful activities, such as listening to ocean waves. Zangoose has a strong immune system and is resistant to venom. It lives in grasslands and savannas.
Zangoose debuted in ZigZag Zangoose, under the ownership of Nicholai. It battled Ash and his Treecko, but suddenly, Zangoose noticed Jessie's Seviper and started to battle it instead. Ash, his friends, and even Team Rocket did not know what was going on, but it was Zangoose and Seviper's natural rivalry that got the two fighting. They were suddenly knocked into a river and Seviper then used Poison Tail, knocking Zangoose unconscious. Brock nursed Zangoose back to health with herbal medicine and left it to rest. Later, Seviper reappeared and engaged it in battle again. After a long and fierce battle, Zangoose finally knocked out the Fang Snake Pokémon with a Crush Claw.
In The Semi-Final Frontier!, a Trainer's Zangoose went up against Tobias during the Lily of the Valley Conference finals. It battled his Darkrai off-screen, but as with the other five Pokémon owned by its Trainer, it was easily defeated by the Pitch-Black Pokémon.
Zangoose certainly has a brave side, using its sharp claws to fight back against foes. But it actually seems to enjoy peaceful activities, like listening to the sound of the ocean waves or nearby singing.
Zangoose is likely based on the mongoose, a cat-like carnivore that is well known for its ability to hunt and kill venomous snakes. It also bears a physical resemblance to the Turkish Angora and Persian cat breeds. The rivalry Zangoose shares with Seviper is based on the relationship both cats and mongooses have towards snakes.
Zangoose may be a combination of 斬 zan (slash) and mongoose.