For Claymation figures, the easiest way to create blood is to make downward grooves into your material and then use bright red paint or an indelible marker to animate your blood. You might be able to experiment with liquid materials, but be warned that, depending on your character’s pose, the liquid may bleed too quickly between frames to be captured correctly on film.
A wonderful way to create a Claymation “spurting” effect is to take several different lengths of wire and cover them with red clay. You can place these into the figure’s wound, and alternate the wires between each frame in order to vary the lengths of each spray. During the post-production phase of your project, add a bit of motion blur in order to create a less disjointed look, and voila! You have created a mortal injury.
If you would like to experiment with more realistic liquids, it might be fun to examine the possibilities of Karo syrup. Use several different shades of food coloring to determine what works best for the style of your particular film.
Materials such as K-Y jelly, Vaseline and hair gel can also be dyed and are more viscous than other liquids. You can use a straw to gently coax movement from your “blood”, and also use these products to replicate other jellied unmentionables.
If it becomes necessary to display interior organs, you may want to use a pasta press to create pink or reddish-brown intestines. If you do not own a pasta press (and do not want to purchase one), you can use the palms of your hands to quickly roll spare clay into long,