With hair this gelled I guess you don't need a helmet.
Hats off to this kids parents. The costume's even cooler on a little kid.
This one was made for just $30 from cardboard. See the making of here.
Master Chief costumes also come in blue for those who don't like to wear green.
But if you want to get the girls try for a red Master Chief costume.
Note: Unless you have a lot of money or know someone who's a professional costume designers don't even attempt to go out this Halloween as Master Chief. As these photos show you're costume is going to pale in comparison to these kick ass examples.