The technology conglomerate Softbank has acquired Boston Dynamics, the firm known for its often terrifying animal- and human-like robots, from Alphabet.

Back in 2013, Alphabet went on somewhat of a robot-buying binge. Led by Android creator Andy Rubin, the company covered all the bases, making acquisitions that included: Boston Dynamics and Schaft (which both make legged robots); Redwood Robotics and Meka (robots that grasp objects); Industrial Perception (computer vision for warehouse robots); Holomni (wheeled robots); and Bot & Dolly (movie-set robots).

But when Rubin left Alphabet in 2014, the firm’s robot master plan appeared to falter. It’s since made no secret of wanting to sell Boston Dynamics. The reasons for that aren’t totally clear: it may have been a bad cultural fit (with Boston Dynamics' obvious military origins and aspirations), or it may simply be financial—it’s not obvious, after all, how many giant robo-dogs a company is ever going to sell.

Now the Japanese technology conglomerate Softbank has taken the company off Alphabet’s hands. At the same time, it’s also acquired Schaft, a Japanese firm that also makes legged robots that have taken part in the DARPA Robotics Challenge. But the news here, according to SoftBank chairman and CEO Masayoshi Son, is all about Boston Dynamics. That much is clear based on a statement he released:

"Today, there are many issues we still cannot solve by ourselves with human capabilities. Smart robotics are going to be a key driver of the next stage of the Information Revolution, and Marc and his team at Boston Dynamics are the clear technology leaders in advanced dynamic robots.”

One interesting observation on the deal—about which no figures have been published—is that SoftBank is clearly betting that legs are important in the future of robotics. It could presumably have acquired other companies off of Alphabet, but instead chose to buy the two that create machines that move like humans and animals.

SoftBank's history with humanoid robots isn’t too compelling so far: its chirpy Pepper robot, designed to assist people in offices and stores, hasn’t proved to be a commercial success. It will hope to do better with Boston Dynamics, and the purchase makes sense given that Japan's aging population is expected to create a huge market for robots that can help out around the house.

But it’s a bold move. Legged robots are incredibly expensive and difficult to build, and are notoriously difficult to stop from falling over. They’re also power-hungry, as the systems required for balance continually use energy. But they are also tantalizing: after all, a human can scale many surfaces that a wheeled vehicle can’t, so in theory a legged robot would do well in environments that are built for humans. SoftBank may reckon that this acquisition is a strong bet on the future of what robotics might be, even if neither firm is commercially viable at the moment.

Softbank has been on a buying and investing spree of late, and appears determined to insert itself into any area of technology it can. It recently acquired the British chip designer ARM, invested $4 billion into chipmaker Nvida, and turned the London-based simulation startup Improbable into a unicorn. It also launched a $100 billion investment alongside Saudi Arabia, much of which will be invested in the U.S. Some walking robots sprinkled atop all that can't hurt.

(Read more: Reuters, “Google Hasn’t Given Up on Robots,” “The Latest Boston Dynamics Creation Escapes the Lab, Roams the Snowy Woods,” “Personal Robots: Artificial Friends with Limited Benefits”)