The Yip Yips (also known as the Martians or aliens) are characters on the popular American children's television show Sesame Street. They are interplanetary visitors, from the planet Mars(in the first skit, as soon as they descend, their first words to each other are "...Not Mars." "Nope."). They marvel at devices such as clocks, telephones and computers. When frightened, each covers its face with the lower part of its jaw while making a distinctive "goom" noise.