This dripping animation designed by Johan Karlsson looks like it will be a great addition to the Halloween section if it was in green or red. The effect feels like what you might see when you throw paint on to a wall.
If you are having trouble with the pen, try the archived copy on GitHub
Paint Dripping Snippet
See the Pen Solid Black | Dripping by Johan Karlsson (@DonKarlssonSan) on CodePen.0