Something tells me this isn’t Frank Herbert’s official explanation for how the Pain Box in Dune works; but nevertheless, here’s a method for building your very own ad hoc phantom pain container, perfect for coaxing your lily-livered friends and children to sticking their trembling hand into.
The enigmatic device that triggers intense pain without doing a lick of physical harm can be approximated by abusing a glitch in our pain receptors. This is knowns as the Thermal Grill Illusion, and the way it works is thus: the torturous mirage of searing pain can be created by stimulating pleasing coolness and pleasant warmth simultaneously. All you need inside your elaborately and sinisterly adorned pain box is a grill-like grid with alternating cool and warm rods placed side-by-side. To give you an example of what we’re talking, one researcher induced the effect using frozen and microwaved hotdogs—likely a first for the scientific method. Just be careful when trying this at home because things can get dramatic:
If you want to read more about the fascinating phenomena, head on over to io9.