Zangoose is a bipedal Pokémon resembling a cross between a mongoose and 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, 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 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.
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 and its rival Seviper share several characteristics, such as being in the FieldEgg Group, residing in the same Friend Area, and being the only two Pokémon with a base stat total of 458.
Zangoose and Seviper also have the exact opposite Experience group, with Zangoose being in the Erratic group and Seviper being in the Fluctuating group.
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.