The Last Guardian finally released earlier this year to decent critical acclaim. So this Halloween, why not revisit the game that inspired it all: Shadow of the Colossus. This striking stencil outlines an iconic shot from the game.
While there are no "official" (read: pumpkin-specific) stencils to work with for your carving, there are plenty of images you can use just fine. The stencil linked above is probably your best bet, but this variation -- which includes trees and is lacking the horse -- is a great alternative.