In order to make fake blood, for special effects or for Halloween, you will need the following: Potassium Thiocyanate (KSCN), Iron (III) Chloride (FeCL3), which is also known as ferric chloride or may substitute Iron Nitrate (Ferric Nitrate). You will also need water or dihydrogen monoxide. To begin add KSCN to the water. Stir. Add FeCL3. Stir it until it dissolves. The chemical reaction causes the liquid to appear to be the color of blood. This can also be used to create secret messages, by allowing the message to occur on the paper. It can be used to fake injuries, by allowing the chemical reaction to occur on your skin.