Instead of getting my chalkboard paint out I have used black poster board many times for different smaller projects.... (theinspiredroom.net)
I actually went out and bought black poster board to tape to the walls to see if a black feature wall would work. (foxdenrd.com)
The fake blood on the gloves were made using red paint markers, the biohazard sign was created with black poster board that cost less than $ 1.00, and the Halloween biohazard bags that I turned into candy bags were purchased from Amazon. (adasinteriordesign.com)