Halloween // Anyone have suggestions for temporary hair dye to go with a costume?

I'm trying to put together a John Constantine costume for the upcoming holiday and have everything I need (tan trenchcoat, black pants and shoes, red tie, candy cigarettes, ect.) except for a proper hair tint.

I'd rather avoid a wig and get something that looks more real, so I was hoping someone here could recommend a good temporary blonde hair dye; something that can get a mid-to-dark brunette to the proper color without doing something drastic like bleaching and can wash out somewhat easily.

Any suggestions would be helpful.