From the folds of her gown, she lifted a green metal cube about fifteen centimeters on a side. She turned it and Paul saw that one side was open – black and oddly frightening. Paul slowly put his hand into the box. He first felt a sense of cold as the blackness closed around his hand, then slick metal against his fingers and a prickling as though his hand were asleep…
“What’s in the box?”

It stopped! As though a switch had been turned off, the pain stopped… “Take your hand from the box, young human, and look at it.” He fought down an aching shiver, stared at the lightless void where his hand seemed to remain of its own volition. Memory of pain inhibited every movement. Reason told him he would withdraw a blackened stump from that box. “Do it!” she snapped. He jerked his hand from the box, stared at it astonished. Not a mark. No sign of agony on the flesh. He held up the hand, turned it, flexed the fingers. “Pain by nerve induction,” she said. “Can’t go around maiming potential humans. There’re those who’d give a pretty for the secret of this box, though.”

also, Khrone, the Face Dancer leader, tried to use pain boxes to awaken the Baron Harkonnen ghoula. except it didn’t work. so he put one on each of the Baron’s hands and feet. Khrone even built a full body pain box, but all it did was give the ghoula a boner.