Down Roll is available in the Creator tier and Pro tier.
Down Roll smoothly and evenly moves the layer from above the viewer to below the viewer, like rolling credits. It positions the layer above the viewer, just out of view, at the first frame of the layer, and moves it to below the viewer, just out of view, on the final frame.
There are no controls for the Down Roll behavior. The speed of the animation is determined by the size and duration of the layer. To speed up the movement, shorten the layer duration. To slow down the movement, extend the layer duration.