It's a bird, it's a plane, it's one of up to 25 giant surveillance balloons currently floating over the Midwest and spying on everything in their path.

According to documents obtained by The Guardian, the U.S. military is currently in the process of testing a large-scale surveillance system made up of floating radar designed to monitor everything from individual cars to entire cities.

"Conduct high altitude MESH networking tests over South Dakota to provide a persistent surveillance system to locate and deter narcotic trafficking and homeland security threats," reads an FCC document authorizing elements of the test.

The test, which the Guardian reports began in July and runs through September, involves high-altitude balloons floating at heights of up to 65,000 feet. The devices are equipped with a range of sensors, and call to mind the Joint Land Attack Cruise Missile Defense Elevated Netted Sensor System (JLENS) pictured above.

You may remember the JLENS from back in 2015, when one of the tethered blimps became detached from its mooring and began floating around Pennsylvania, dragging its giant cable and causing mayhem in the process.

I should know better by now, but even I still have trouble believing that "runaway surveillance blimp" is actually a thing. — Edward Snowden (@Snowden) October 28, 2015

Unlike JLENS, however, the most recent additions to the persistent surveillance of U.S. citizens are designed to move about. For now, their path reportedly includes Illinois, Minnesota, Wisconsin, Missouri, and Iowa.

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So the next time you're outside, perhaps enjoying a Midwestern summer BBQ, feel free to look up and give a little wave. Just don't do anything that could be misconstrued as suspicious — after all, the balloons are watching.