The reason for this is because I have seen a few video's with these examples such as "Train - Hey Soul Sister"
Stop motion (also known as stop action) is an animation technique to make a physically manipulated object appear to move on its own. The object is moved in small increments between individually photographed frames, creating the illusion of movement when the series of frames is played as a continuous sequence. Clay figures are often used in stop motion for their ease of repositioning. Motion animation using clay is called clay animation or clay-mation.