Water
A low-viscosity Newtonian fluid. It breaks down the thickness of the syrups, making the mixture highly fluid. It increases the flow rate, which is necessary if you want the blood to run fast, splatter, or spray through a nozzle.
Light Corn Syrup
This is a highly viscous, non-Newtonian fluid. It provides the thick, sluggish flow of real blood. It catches the light perfectly, creating a realistic, glossy sheen that prevents the mixture from looking watery
Cornstarch
This is a powerful thickening agent that creates a shear-thickening (dilatant) fluid when mixed with liquids. It blocks light to give the blood realistic opacity. It also slows down the flow speed, making it stay inside a "wound" rather than dripping away instantly.
Cocoa Powder
This acts as a particulate texturizer. It does not dissolve fully, leaving microscopic grains suspended in the liquid. This alters the texture to mimic clotting, drying, or scabbing blood, while also increasing viscosity
Red Food Coloring
This has a negligible, water-like viscosity. However, because you have to add a large volume of red dye to get a deep color, it slightly thins out high-viscosity bases like pure corn syrup
Dish Soap
Soap introduces surfactant properties and a moderate, silky viscosity. It reduces surface tension, allowing the blood to coat surfaces evenly and smear realistically without instantly breaking up into beads or droplets.