An Oil Spill
This is a true last-minute costume, and could be pretty easy: any shiny, dark clothes you have on hand could work to depict the devastating ecological damage done by oil spills. If you’re in a pinch, a couple garbage bags with holes cut out of the top could represent an oil slick nicely. If you want to get really literal, you could pour vegetable oil on a black shirt and wear the stain proudly. Print out some Big Oil logos to stick on your garment of choice and you’re good to go.
