willfosho:No. 240: Magby aka Buby (ブビィ). Magby’s state of health is determined by observing the fire
willfosho:No. 240: Magby aka Buby (ブビィ). Magby’s state of health is determined by observing the fire it breathes. If the Pokémon is spouting yellow flames from its mouth, it is in good health. When it is fatigued, black smoke will be mixed in with the flames. -- source link