Indy Mogul has posted two Instructables on grisly special effects for film that you can do yourself, How To Rip a Heart Out of Someones Chest (a la Indiana Jones and the Temple of Doom), and a Decapitation Effect. With videos. These could be handy for Halloween, too! Link to heart effect. Link to head affect.
Have you ever seen the edible flesh eating worms for Halloween? I was glad I didn't eat before looking at the picture.
http://imakeprojects.com/Projects/fleshworms/