Scientists have created a tiny robotic system that can transition from solid to liquid and back again, bringing a bit of classic sci-fi lore to life while they're at it.

"Giving robots the ability to switch between liquid and solid states endows them with more functionality," says Chengfeng Pan, an engineer at The Chinese University of Hong Kong who led the study.

As if to gesture at Terminator-inspired night terrors, Pan and colleagues demonstrate this increased functionality by placing one of their miniature robots in a simulated jail cell and showing how it might escape.

The particles are embedded in gallium, which is a metal with a very low melting point of just 86 degrees Fahrenheit (about 30 Celsius), creating a substance that flows more like water than other phase-changing materials, which are more viscous.

"What we're showing are just one-off demonstrations, proofs of concept, but much more study will be required to delve into how this could actually be used for drug delivery or for removing foreign objects."

Hopefully the list of foreign objects that need removal won't ever include weaponized miniature melting robots, as they might prove difficult to track down and extract.