What you need: a T-shirt, a marker, and a strong defense against cynics

All you’ll need for this is a T-shirt you won’t want to wear again (or, to be honest, a T-shirt that will become your go-to Halloween costume for years to come). All you need to do is write “Error 404: Costume Not Found” on a white shirt and your nerdy, low-effort costume is ready. You should be prepared to be the most comfortable person of the night, but also the costume that gets the most eyerolls.