“Underwater Ghost”: China’s Jellyfish Robot Blurs the Line Between Biology and Stealth Technology
At the Northwestern Polytechnical University (NPU) in Xi’an, researchers have developed one of the most lifelike bionic platforms of recent years — a jellyfish-inspired robot nicknamed the “Underwater Ghost” (水下幽灵). From just a few meters away, it is nearly indistinguishable from a real jellyfish: a translucent dome about 12 centimeters in diameter, smooth pulsations, and silent gliding through the water. But instead of stinging cells, it carries a camera and an AI chip, and instead of muscles, it uses novel electrohydraulic actuators and hydrogel-based electrodes that replicate the jellyfish’s pulsating propulsion with an energy consumption of only about 28.5 milliwatts.
Engineers at NPU achieved a rare balance: the robot weighs only 56 grams, remains fully transparent, generates almost no noise, and can move for long periods thanks to its ultra-low power consumption. For this reason, it is not considered a short-term demonstration platform but rather a tool for long-term underwater monitoring — from ecologically sensitive waters to deep observation zones where conventional submersibles are too intrusive and disruptive. The built-in AI chip processes visual and sensory data directly on board: the “ghost” can hover in a current, recognize and track specific targets, and maintain stability even in dynamic aquatic environments.
However, its very “invisibility” raises questions. To a fish, a sea turtle, or a diver, this robot truly looks like an ordinary jellyfish — meaning it could potentially alter animal behavior or attract predator attacks. Biologists have already pointed out that such perfect biomimicry risks turning the robot from a mere observation device into an active participant in the ecosystem, albeit an artificial one. The developers, in turn, emphasize that the “Underwater Ghost” was conceived as a gentle alternative to loud metallic drones and, when used appropriately, could reduce overall stress on marine habitats: it moves slowly, leaves a minimal acoustic trace, and lacks powerful thrusters or lights.
The strategic dimension is equally clear. China is not just showcasing an impressive piece of marine biomimetics but also expanding its stealth-oriented underwater toolkit — from scientific monitoring and infrastructure inspection to potential defense applications. The “Underwater Ghost” is no longer a futuristic concept of soft robotics; it is a real, operational platform born in a university lab, now closely watched by both oceanographers and defense analysts.
Official description and images of the robot are available on the Northwestern Polytechnical University website: en.nwpu.edu.cn
