I know a lot of people are swaying toward the dark side in their Halloween crafting and for a couple of years now, I've been wanting to make bloody white pumpkins, so I finally did!
For the drippy one, I basically used Tulip 3-D paint in Bright Red and squeezed it on in a drippy fashion along the ridges of the pumpkin. I also covered the stem.
For the fang one, I used a construction nail and dug it into the pumpkin in two spots, then squirted the 3-D paint inside and drug the tip down and created a blob of blood at the bottom of the drip.
It was really fun and super fast!
For more info on this project, you can see this project on my blog: http://swelldesigner.blogspot.com/2009/10/bloody-pumpkins.html