Death Shadows: The Flesh Eaters of Skid Row

On a sunny morning three homeless residents of an abandoned industrial park discover the corpse of a man lying on the pavement with a notebook of strange physics formulas. To the horror of the surviving witness, touching the remains causes two of them to instantly disintegrate into skeletons, their flesh chewed off the bone in seconds. Soon, a pair of drug dealers, two prostitutes and their pimp, three college students, a real estate agent and his assistant, and other vagrants of the inner city slum converge on the desolate territory and make the terrible discovery that they cannot leave. Any attempt to cross the shadows that ring the outermost boundary of the city block leads to instant death, for invisible monsters lurk in the absence of light along the decrepit buildings and fences, devouring those who try to flee.
To add to their dread, they only have until the setting of the sun to find a way to escape, before the entire territory of their phantom prison is swept over with the fatal darkness