There are lots of versions of these out there—even necrotized zombie ones—but here are the instructions from Karen Pack's Pinterest board (thanks!) with this great picture.
Simply roll out some sugar-cookie dough into a thin line, apply an almond sliver, draw knuckles with a knife, then bake as directed. Brush with a little cocoa-powder to make the hands look dirty.
Oh, do that, please. We're peckish for elevenses already.