Pour 1/2 cup of corn syrup in a bowl. Use the clear corn syrup. Depending on how much blood you want to make, you can add more or less.
Mix one tablespoon of water to the syrup. This will help lessen the viscosity of the syrup, but not so much that it takes away from the clinging effect. You can add up to a half cup of warm water to make the blood more runny or to use it in a squirt bottle.
Add between four and six drops of red food coloring to the mix, depending upon the color of blood you're going for. Stir the mixture with a spoon. If you want more red, add drops of food coloring until the color suits your needs. Add a squirt or two of chocolate syrup to darken the blood or create an older, dried blood effect.
Pour blood in a plastic squirt bottle and set the nozzle to mist. This is a great way to create a realistic blood spatter on clothes. Mix fake blood with oatmeal and wax to create scabs, open sores and wounds. To create stab effects, pour the fake blood mixture into plastic baggies and place them strategically on your body. Use a concealed safety pin to puncture the baggies when you need to create the appearance of spilled blood.