Google's cold, mechanical grip on the future continues to tighten.

The latest robotics firm to be snatched up under Android-creator Andy Rubin's recent acquisition spree is none other than Boston Dynamics, the Pentagon contractor responsible for some of the most advanced military robots of the last several years. You may have seen several of its inventions on this very website.

While the terms of the deal are unclear, the DARPA-funded robotics lab has a reputation for developing "extraordinarily agile" bipedal and quadrupedal robots capable of traversing difficult-to-navigate terrain, as the New York Times puts it. Although Google plans to honor "existing military contracts," executives say Google has no intention of becoming a defense contractor. Google declined to pin an exact figure on the Boston Dynamics purchase.

So what kind of world-class military prototypes are we talking about? Most are biomimetic companion-bots built to haul heavy payloads for foot soldiers. (The more disquieting potential uses are perhaps best left to the imagination.)

Here, for example, is WildCat — a cheetah-inspired machine that can prance and gallop at speeds up to 16 mph.

Atlas, Boston Dynamics' ongoing experiment with the humanoid form that can retain its balance when thwacked with a 20-pound medicine ball:

The Sand Flea jumping RC car, which, well… look:

And the stout and sturdy BigDog, which can trot payloads in the several hundred pound-range up snow-covered mountainsides:

And those are just the public-facing experiments.

Andy Rubin, who recently re-emerged as the project leader behind the purchases of robotics laboratories all over the world, seems uncharacteristically upbeat about the purchase:

Indeed, Google's "don't be evil" mantra never carried so much weight.