Quilava is a quadrupedal Pokémon with a long, slender body. The top half of its body is a dark blue-green, while its underside is cream-colored. It has triangular ears with dark red interiors, a rounded snout, and triangular red eyes. Each of its paws has three toes. It has five red spots on its body that can project flames: two arranged vertically on its forehead and three lined up horizontally on its rear. Before a battle, Quilava turns its back so its flames face its opponent. It battles using these intense flames in combination with gusts of superheated air. Its own fur is non-flammable, which protects it from other fire attacks. Quilava tends to be rare in the wild, but can sometimes be found living on grasslands.
Quilava shares its category with its evolved form and Entei. They are all known as the Volcano Pokémon.
Coincidentally, they all are capable of learning Eruption.
Quilava's body is similar to most animals in the weasel family, particularly stoats due to its lack of a tail and the fur on its upper body being significantly darker than that on its underbelly. However, the pattern distribution and shape of Quilava's flames closely resembles the quills and crest of the crested porcupine, especially in its earlier sprites.
Quilava's 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 ヤマアラシ (山荒) yama-arashi (porcupine).