Creative effects supervisor Erik Porn is a movie blood expert. His credits include “Teen Wolf” and “The Wretched.

When Porn starts making the blood for his films, his first step is purchasing methocel, a common slime ingredient seen covering Bill Murray’s character in “Ghostbusters.”

All it takes to make movie-level fake blood are ingredients found in the baking aisle. Porn uses corn syrup, red food coloring and cocoa powder to start. Blue and green food dyes are added to “give that deep brown look to your blood,” he says.

Porn also adds corn starch to the blood to thicken it and give it the appropriate consistency — and then it’s ready to be used. With completely edible ingredients, it can even be used as “mouth blood.”

Five pumps of hand soap can also be added to help the blood “stay on your hands a little bit better [so] it goes into all the cracks and crevices in your skin.” He adds, “It’s a nice recipe if you want something that will drizzle down your face.”

When creating the effects and monster for the IFC horror film, “The Wretched,” Porn says he didn’t have many options while shooting in Michigan and went to the grocery store for all of his bloody ingredients.

In movie, troubled teen Ben, played by John-Paul Howard, is sent to live with his father for the summer in a coastal town. Ben busies himself until he discovers that his neighbor Abbie (Zarah Mahler) is actually possessed by a 1,000-year-old witch who preys on children and removes all traces of their existence.