The Pentagon is planning to design "vampire" drones that can disappear in daylight in order to allow them to drop supplies to hidden Special Forces without letting the technology fall into enemy hands, according to the Daily Mail. The Defense Advanced Research Projects Agency (DARPA), who is funding the project, said the drones will "fully vanish within four hours of payload delivery or within 30 minutes of morning civil twilight (assuming a night drop), whichever is earlier."

"These precision vehicles must be guaranteed to rapidly physically disappear following safe payload delivery," said DARPA.

The drone will ideally be able to deliver materials to hard-to-reach locations, eliminating the need to clear away a landing spot, according to Newsmax. Furthermore, DARPA is going to ensure that the pieces of the craft are not visible to the naked eye after they have disappeared and never exceed the size of a grain of sand.

The drone is a part of the Vanishing Programmable Resources (VAPR) program and will take advantage of recent technological breakthroughs in advanced polymer sublimation, which refers to the transformation of a solid substance into a gas, according to Defense One.

Despite these goals, DARPA acknowledges the difficulty in creating drones that are both effective and possess the ability to disappear.

"Achieving appropriate transience rates without degrading the structural properties may pose a significant technical challenge when engineering existing transient materials, for example sublimating polymers," the organization said.