In UFO/Unsolved Mysteries circles, "mute" isn't a button on yout TV remote. It's short for "mutilation" of livestock or other animals.
Since the 1960s or before, folks have been finding their free-roving animals -- livestock, dogs in the backyard, horses -- dead and cut up, sometimes with parts removed.
Sometimes investigations point to predators. Other times, cellular damage and other findings indicate a technological cause.
Once in a while, lights in the sky or other activity hs been noted where animals are later discovered. Occasionally, an animal has been found with its legs broken in a way only possible if it were dropped from a height.
The whole cultural "meme" of black helicopters spying on you came from the cattle mutilation tales.
Now, explanations have run from from them ol' little green men, to government experiments. The aliens want to modify animal flesh as part of their plans to create an alien-human hybrid. With these views, you'll often hear that pig DNA is nearly identical to human DNA, etc.
The government side of the theory bank usually takes the view that the US government (or parts thereof) are taking samples from randomly "free-range" critters to test for radiation poisoning or some such. One of the latest offshoots proposes that the animal parts taken are analyzed for the presence of prions, the chief indicator of Mad Cow Disease, BSE (Bovine Spongiform Enchephalitis).
All I know is, when I read about such things I get hungry for a hamburger!