The block will make its sprite continuously pen a trail wherever it moves until the Pen Up block is used. The color, size, and transparency of the trail can be changed with other blocks.
This block is used most frequently in projects that require art to be drawn. When a sprite will continuously pen a trail (for example, a project where the goal is to fill the whole screen), most projects will use this block. This block is also commonly used in one sprite one script one costume projects.