A dark funnel-shaped cloud that reached from sky towards ground is called a

A violent storm with a very strong wind that blows in a Circle is called Tornado. 

A tornado forms from a large thunderstorm. Inside thunderclouds, warm, humid air rises, while cool air falls--along with rain or hail. These conditions can cause spinning air currents inside the cloud. Although the spinning currents start out horizontal, they can turn vertical and drop down from the cloud-becoming a tornado.