Halloween // Fake Blood recipes

Good afternoon, fellow horror friends. I thought this would be the best place to get a hand on a question I've got.

Long story short, I'm teaching a class on Forensic science, and soon I'll be conducting a lab on Blood Spatter analysis. Turns out I have much less fake blood than I thought I did, and now I don't think I have time to order anything legitimate. And to be totally honest, I wasn't thrilled with how the store bought stuff looked in regards to teaching.

So, does anyone out there have any good recipes for fake blood I can just make at home? I googled a few ideas, and I can use those, but for me and what I need, looking like blood isn't enough, it needs to act like it as well. Needs to be a little thicker so it flows properly when making stains.