Magby has a red body, except its stomach which is a yellow color and is in the shape of a flame. It has a single red spike on its back and a long red tail and there are many red lumps on its head, resembling hair. Around Magby's neck there is a black metal shackle.
Its body temperature and the fire that it breathes are constantly over 1100 degrees F. Its health is determined by the state of its flame; healthy Magbys have pure yellow flames, while black smoke is mixed in with unhealthy ones. As it breathes, embers constantly dribble out of its nostrils and its mouth.
It lives in volcanic craters, and an eruption is imminent when many Magby gather in one place.
In the Manga
There is a Magby which is a part of a group of baby Pokémon which escape from the Goldenrod City Daycare Centre in Volume 9.