human
What is the difference between a "funnel cloud" and a "sundog"?
assistant
A sundog is a type of funnel cloud that forms in the sky when there are strong winds blowing across an area with warm, moist air. A sundog usually appears as a bright, circular or oval-shaped object that has a dark center and a lighter outer ring. Funnel clouds, on the other hand, form when cold air from high altitudes meets warmer air at lower altitudes. These clouds can take on many different shapes and sizes, ranging from small wisps to large, rotating columns.