What can make the moon look completely dark as seen from earth?

The moon can appear completely dark from Earth during a total lunar eclipse. This phenomenon occurs when the Earth passes directly between the sun and the moon, blocking sunlight from reaching the moon's surface. During this event, the moon can take on a reddish hue due to the Earth's atmosphere filtering and bending some sunlight into the shadow. However, when fully eclipsed, it can seem to vanish entirely from view.