That is a very interesting Halloween pumpkin which can be colored in few interesting ways to give it a Halloween look using colors common to Halloween. Remembering jack-o-lanterns on Halloween will help color this Halloween pumpkin precisely in a pretty way. First it would be preferred to color the pumpkin with orange color as that is the natural color of a pumpkin. The stem on top of the pumpkin can be colored brown or green. The face of the Halloween pumpkin should be bright like a yellow so it gives a real Halloween look. Two different colors can also be used to color the face like using the same color of eyes and lips and a different color for nose. As for the background it should be a black or in shades of dark gray or adding both together for a perfect scary Halloween look.