I'm watching National Geographic, and it was just showing a wasp which they called the "giant hornet". They discribed its predation on beehives: It starts off decapitating the workers at the hive entrance. It is immune to their stings. "Before long, no honeybees remain alive." It then enters the hive to gorge on the honey. Afterwards, it starts stealing the HB's brood to feed to its own.
Googling, I found one species, the Asian or Japanese Giant Hornet (Vespa mandarinia Smith, 1852) carries this reputation and is reputed to be a great hassle to Japanese Beeks. The European Giant Hornet (Vespa crabro) was first reported in the U.S. in 1840 New York. In my breif look, I didn't see that it carries the same report with Beeks as the Japanese one does, and I didn't see a report that the Japanese one lives in the U.S...
Anyone with more knowledge on the insect(s)? I would dig deeper myself, but haven't come across it in local beekeeping yet.