Robots keep getting creepier

• Researchers unveiled a smiling humanoid robot with lab-grown, self-healing skin.
• The team from the University of Tokyo used collagen gel to bond living skin tissue to 3D models.
• The researchers said it could benefit the cosmetics industry and help train plastic surgeons.

It's not just nuts and bolts keeping robots together — now they can be made with living skin. Skin that can be made to smile.

Researchers at the University of Tokyo revealed on Tuesday a rather unsettling humanoid robot covered with lab-grown skin. The team said it was able to mimic human skin ligaments by bonding skin tissue to perforated 3D facial molds and 2D robots.

A press release said the team hoped the advancement would be "useful in the cosmetics industry and to help train plastic surgeons."

While the development could prove helpful, some people online reacted to the robot's fleshy skin and facial movements with jokes or said they found it disturbing. One person on X wrote , "You will live to see man-made made horrors beyond your comprehension." Another said : "We don't want this. Nobody wants this. Stop it."

The researchers said that, unlike other materials, biological skin granted these robots self-healing capabilities without requiring triggers such as heat or pressure.

"Biological skin repairs minor lacerations as ours does, and nerves and other skin organs can be added for use in sensing and so on," said Shoji Takeuchi, a professor at the University of Tokyo who led the research.

The researchers said other techniques for attaching skin to surfaces, such as using mini anchors or hooks, limited the surfaces they could use and could cause damage.

But they said that by using a "special collagen gel for adhesion," they could apply the skin to any surface, even a curving or moving one — like a smiling robot.

"The natural flexibility of the skin and the strong method of adhesion mean the skin can move with the mechanical components of the robot without tearing or peeling away," Takeuchi said.

He said the team hoped to create a thicker and more realistic skin by "incorporating sweat glands, sebaceous glands, pores, blood vessels, fat and nerves." He added that by using devices called actuators to imitate muscle movement, the researchers could create humanlike expressions.

This is just the latest development in humanoid robotics, which aims to mimic humans' appearance and functions — sometimes falling into the uncanny valley .

Tesla is developing its Optimus robot , which CEO Elon Musk hopes people will regard "as sort of a friend." Other bots operate on all fours, like Boston Dynamics' robotic police dog .

While you probably don't have to worry about seeing living skin on a production robot anytime soon, the University of Tokyo researchers have at least demonstrated it's possible — even if that means a bit of nightmare fuel for the rest of us along the way.