Before I got into the elaborate creative costume creations, I was the master of last minute costumes. I remember going to Walgreens the night of a party, purchasing one of the garbage bags that were black and had a face of a witch on it. I cut holes in the eyes and mouth, put it over my head and had a great time.
10 Super Easy Last Minute Halloween Costumes
Some of the other one's I remember were: Putting an empty pot on my head and going as a pot-head. I zipped myself in a giant green sleeping bag, slapped two eyes on it and went as Jabba the Hutt. There's also the one where I wore a men's shirt, skirt, messy hair and carried red pumps - I was the walk of shame...
Of course I'm much more mature now. However in case you need a last minute idea or two, here are some great ones.