With that, you cause sensation and spread terror everywhere... Muahahahhahahaa!
What you need is an Orange (yes, no pumpkin, only an Orange) and a knife.
Cut off the peel on the top and bottom of the Orange.
Cut six to eight slices of peel from top to bottom.
Peel Off one of the slices.
Cut a straight line at the center of the slice.
Cut some straight little lines perpendiculars to the first one.
Place the cutted slice in your mouth like a mouthguard.
And that's it!
Ah! And don't forget it, with only one orange, all family are prepared for Halloween, even Grandma!