Ew. I know. But Bloody Brains score extremely high on the effort/impact scale: they take just a few minutes to make, and everybody will have something to say about them. (That something will probably be "ew.")
Note: Popcorn balls are always best when they're super-fresh, but you can make these up to a day in advance provided you wrap them individually in plastic wrap and put them in an airtight container; the jelly will retain its shine really well.