Make your own tinfoil portraits/sculptures. You could buy face masks and give students tinfoil. I think this would work. Would probably look even better on a black canvas or cheaper option, black card.
Cardoard cutouts painted black with the eyes cut out and a glow stick in a little box glued (or duct taped) to the back of the head.if you don't want to do full sized cutouts, you could just do creepy figures in windows.