Quilava is a slim quadruped Pokémon. The top half of its body is blue, while the lower half is cream. Its ears are triangular with red insides, and it possesses a rounded nose and red eyes. It has five red spots on its body that can project flames: two in a somewhat exclamation-mark shape on its forehead and three lined up horizontally on its rear. The fire coming from its head and rear can be launched as a flame attack. It also uses gusts of superheated air as a battle technique. Quilava's fur is non-flammable, so it can withstand flame attacks. Quilava tends to be rare in the wild, but can sometimes be found living on grasslands.
A Quilava appeared in The Champ Twins!, under the ownership of Ryan. It was used in a battle against Ash and Dawn alongside a Croconaw belonging to Ryan's twin brother Bryan. The twins were able to defeat Ash's Turtwig and Dawn's Piplup due to the latter two having a lack of teamwork, but they were defeated in the rematch.
Its appearance is similar to most animals in the weasel family, resembling stoats in particular based on its lack of a tail and the fur on its upper body being significantly darker than that on its underbelly. Its appearance is also quite close to a paca, a South American rodent with a slender body, spotted skin and tiny ears, as well as a badger.
Quilava is a combination of quill (a needle-like hair) and lava (extrusive molten rock).
Magmarashi is a combination of magma and 山荒 yama-arashi (porcupine).