Mari Michaelis, programmer, web designer, graphic artist, and self-professed “paperphile,” maintains a wonderful origami site, called Marigami Origami. On it, she includes a page for a folding project called Mantler’s Bat. This medium skill-level fold was created by origami artist Andrea Mantler. On her site, Michaelis has a link to the PDF instructions for the project and a video that she did (below) showing the fold, step-by-step.
This looks like a rather difficult build and I don’t know that I’d want to fold a lot of them (if I could even successfully manage one). But if you have the patience (and maybe a few press-ganged friends), you could certainly make an impressive contribution to the Halloween spirit with these lovely papercraft blood suckers.
[Thanks to Make: pal Kent Barnes for the link.]