Hal the robot boy is convulsing. His head shakes back and forth so rapidly, it looks like he’s vibrating. His eyelids droop over his blue eyes and his mouth is ajar. He makes no sound, other than the faint whirs of his motors.

Hal was built to suffer. He is a medical training robot, the sort of invention that emerges when one of the most stressful jobs on Earth tumbles into the uncanny valley. No longer must nurses train on lifeless mannequins. Hal can shed tears, bleed, and urinate. If you shine a light in his eyes, his pupils shrink. You can wirelessly control him to go into anaphylactic shock or cardiac arrest. You can hook him up to real hospital machines, and even jolt him with a defibrillator. Hal—which is just now coming onto the market—is so realistic, and these scenarios so emotionally charged, that the instructors who run him in medical simulations have to be careful not to push things too far and upset trainees.

“I've seen several nurses be like, ‘Whoa it moves!’” says Marc Berg, medical director at the Revive Initiative for Resuscitation Excellence at Stanford. “I think that's kind of similar to the idea that if you've driven a car for 20 years and then you got a brand new car, you're kind of amazed initially.”

The company behind this $48,000 robot boy is Gaumard Scientific, which has been developing medical simulators since the 1940s, beginning with synthetic skeletons and anatomical figures. Now, though, the company’s tech has become much more interactive with Hal’s extended family of humanoid robots. Victoria is a robotic woman who gives birth to a baby robot. And Super Tory is a newborn that can help nurses learn to watch for signs of illness in real babies.

Video by Ryan Loughlin

Inside Hal, a combo mechanical-pneumatic system makes him breathe, and a cartridge in his leg allows him to exhale CO2. Hydraulic systems provide fake blood and tears. Servo motors tug on his face, helping him to look angry or scared, among other emotions. He even speaks, with a repertoire that includes shouting for his mother and telling you not touch him. If you like, you can even speak through the robot, with a system that turns your voice into that of a 5-year-old.

One of the reasons for building Hal was to train medical workers on how to approach children, who may not be forthcoming about their symptoms. “They can often do that by facial expression,” says James Archetto, Gaumard’s vice president. To get the expressions right, the company’s engineers worked with pediatricians to fine-tune how an angry or happy child’s face really moves—muscles contracting here, brows furrowing there.