For the past two months, a pair of funny-looking, toaster-like creatures have been busily toting groceries from the Fry's Food supermarket to people’s homes in Scottsdale, Arizona. Now, residents of the Phoenix suburb should get ready to see a lot more of these bots: Nuro, the self-driving startup that builds and operates the diminutive automatons, announced this morning it has received a $940 million investment from the SoftBank Vision Fund.

The deal—the biggest investment in a self-driving company in recent months—continues SoftBank’s steady march into the transportation industry: The Japanese giant has also invested in Uber, Mapbox, and parking “platform” ParkJockey. Last year, it put $2.25 billion into General Motor’s self-driving arm, Cruise.

Nuro, which is focused on local deliveries, makes a logical addition to SoftBank’s roster. The Silicon Valley startup was founded in 2016 by Dave Ferguson and Jiajun Zhu, both early and longtime members of Google’s self-driving car effort (now a standalone Alphabet company known as Waymo). In the past two and a half years, it has built a team of 200 full-time employees and about 100 contractors, and produced a few copies of its R-1 robot, which is a bit smaller than a standard sedan. It can carry more stuff than sidewalk delivery bots being developed by companies like Marble, and while it drives in the street, its slim profile makes moving safely easier, Ferguson says.

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Last summer, Nuro announced a deal with grocery mega-chain Kroger (which owns Fry’s Food) to deliver groceries for some Scottsdale customers, and in the fall it started a version of the service using its technology on modified Toyota Prius cars, so it could keep safety operators behind the wheel. In December, the team put two human-free R-1s into the field, with a human-filled chase vehicle tailing each. Having those humans around lets Nuro study the practical elements of the service, like how customers handle getting their good from a robot. The next step, Ferguson says, will be letting them go solo and monitoring them from afar.

Nuro will use SoftBank’s money to build a proper fleet, expanding its service beyond a single Scottsdale zip code and working with new partners. “Now we’re really looking to make this a real thing,” Ferguson says. And the company is looking to bring in revenue sooner rather than later. “We’re not going to be doing R&D for five years.” He declined to say where the next service might operate, beyond somewhere with a “sizeable population.” Nuro also licenses its software to self-driving truck startup Ike, and Ferguson says similar deals are a possibility.

So far, use cases for self-driving technology have mostly focused on taxi services and long-distance trucking, but Nuro seems to be eyeing a nice niche. The distance covered by the average shipment in the US has dropped well below 100 miles in recent years. “Last-mile delivery is a massively growing business,” says Andrew Tipping, who runs the transportation team at PwC’s Strategy& consulting business. Groceries aren’t the easiest thing to deliver in general—they’re heavy, cheap, and require varying degrees of refrigeration—but Americans might spend up to $100 billion annually online grocery shopping by 2022, per a Nielsen study. “It’s such a big market, I am sure that one of these companies will crack it,” Tipping says.

Indeed, the great deliverer itself took a big step into the autonomous driving space just last week: Amazon is now an investor in Aurora Innovation, the startup helmed by Ferguson and Zhu’s former Google boss, Chris Urmson. Because if moving stuff a lot of stuff super-efficiently with humans is good, doing it with robots is probably better. And while it does mean you don’t have a human there to carry the bags to the doorstep, or know to leave them if the customer’s not home, it could make the delivery service cheaper.