HAYWARD, Calif. — On a sunny afternoon in this industrial town south of Oakland, Gui Cavalcanti is examining a trencher. It’s a nasty-looking, toothy piece of equipment that you’d ordinarily attach to the front of a Bobcat vehicle if you needed to dig a ditch in rocky soil. But Cavalcanti wonders how the trencher would work affixed to the arm of a massive warrior robot. “We want weapons that are dangerous to other robots — that can tear hoses and cut wires — but that don’t immediately risk killing the robot’s pilot,’’ he says.

Cavalcanti and his cofounders at MegaBots have a vision that you can summarize in three words: Giant. Fighting. Robots. “We are an entertainment company that builds robots,’’ he says, “and we’re trying to make robot battles a sport,’’ a hybrid of NASCAR, Transformers, and Ultimate Fighting Championship. Or perhaps an extra-large version of the TV series “Battlebots,’’ with human pilots sitting in the cockpit of the 16-foot-tall robots instead of safely outside of the ring, twiddling remote controls.

“The idea that we can invent a completely new form of sports entertainment for the 21st century is a very big idea,’’ says Joshua Adler, a New Hampshire-based investor who was the first to back MegaBots. “Most professional sports were invented not in the 20th century, but in the 19th century. We think the time is right to introduce some new sports for the millennial generation and beyond.’’

It won’t be easy, but MegaBots has already overcome some very long odds since it was founded in Somerville in 2014.

Cavalcanti studied engineering at Olin College in Needham, and then went to work for Boston Dynamics, a company that designed first-of-a-kind walking robots like BigDog and Atlas for the Department of Defense. (It’s now owned by Google.) Cavalcanti later helped create Artisan’s Asylum in Somerville, a communal workshop for artists, hobbyists, and entrepreneurs. He was also a contestant on a short-lived reality show on Discovery Channel called “The Big Brain Theory,’’ where teams competed in engineering challenges like bridge-building.

About three years ago, he was brainstorming with Adler about different kinds of jobs that robots might be able to perform. “I was thinking about using robots to detect and fix pipeline leaks, and then we brainstormed about the construction industry — maybe they could lay bricks faster,’’ Adler says.

Eventually, Cavalcanti half-jokingly tossed out the idea of two robots fighting. “We were trying to be studious, and think about societally beneficial uses,’’ Adler says. “But I was like, ‘Giant robot battles — who wouldn’t watch that?’ I felt like somebody had to do it, and why not us?’’

In June 2014, Adler wrote a check to allow Cavalcanti to form the company and start the design process. But other investors were hard to find in Boston, even after MegaBots had built a prototype robot that looked cool, but didn’t do much. “It was too early for us,’’ says Bob Higgins of Causeway Media Partners in Cambridge, a firm that invests in sports, media, and technology ventures.

A crowdfunding campaign on Kickstarter failed to raise the hoped-for $1.8 million, bringing in just $65,000. (The company received none of the cash, in accordance with the website’s rules.)

“It probably would’ve been curtains at the end of 2014,’’ Adler says, if not for a sugar daddy who materialized at the last minute. Cavalcanti had met Carl Bass, chief executive of the design software company Autodesk, at a conference, and shown him concept drawings of what the MegaBots would look like. Bass wanted to get the team using Autodesk’s software for the project — instead of a competitor’s. That conversation turned into an offer of free workspace in San Francisco, a monetary lifeline, and a collaboration with the California-based company. Cavalcanti and MegaBots cofounder Matt Oehrlein packed up and headed west in December 2015.

They showed off versions of the robot — including one that blasted a car with grapefruit-sized paintballs — at various festivals around the Bay Area. But it wasn’t until Cavalcanti and Oehrlein decided to challenge Kuratas, a Japanese-made giant robot, to a duel that the notion of robot battles really started to build momentum. A YouTube video posted in June 2015 observed, “You have a giant robot, we have a giant robot. We have a duty to the science fiction lovers of this world to fight them to the death.’’ It has been seen more than 7 million times, and it led to another Kickstarter campaign, which sought to raise funds to prepare for the face-off. That one successfully raised $554,000.

The company has now raised just over $4 million in funding. Investors in California, Adler says, “were not obsessed with the plausibility of the idea, but the size of the idea. They wanted to know, ‘What is the maximum potential of this if this works? That’s the lesson they’ve learned from companies like Google and Facebook and Uber.’’

In a rented warehouse in Hayward, MegaBots employees are racing to finish the third version of the robot — the one that will take on Kuratas. The initial challenge video said that the US vs. Japan match would take place in mid-2016, but that deadline blew by, and Cavalcanti now doesn’t want to be specific about when it might happen. As they test different weaponry, or gauge how serious it would be if a robot keeled over with the pilot inside, they’re producing short videos for YouTube. Some of the members of the MegaBots production crew also worked on the long-running science show “Mythbusters,’’ filmed just a few miles up the highway. (“Mythbusters’’ co-host Jamie Hyneman has also done some consulting work for MegaBots, but says via e-mail, “I detest competitions.’’)

Cavalcanti says the objective is to accumulate an online following before negotiating with networks who might want to become the ESPN of the future robot fighting league. “What you see on YouTube is a very deliberate strategy,’’ he says. “We want to own our brand, produce our own content, and build our own audience.’’ At that point, he adds, “the conversations with the networks are very different, versus when you go in with zero leverage.’’

Greg Munson, co-creator of the show “Battlebots,’’ which just finished its second season on ABC, says that approach may prove wise.

But there will still be challenges on the way to becoming anything approaching a mainstream sport. One is how expensive it will be for a team to build its own MegaBot to participate in the league; Cavalcanti estimates it at about $500,000 for parts, not including assembly time. By contrast, building a Battlebot costs about $15,000 to $20,000, Munson says. Another challenge, he adds, will be forging a set of rules so that clashes will be exciting, as opposed to “rip-your-face-off-boring.’’

“The challenge Gui and Matt have as they’re building the sport is to ensure that the entertainment value is there — things like which weapons are going to be awesome but not kill the pilots,’’ Munson says. They’ll also need to raise even more capital.

Despite the hurdles, Munson is enthusiastic about MegaBots. “I don’t know about you, but I’d have a front row seat to watch two giant mechs battle,’’ he says, describing Battlebots and MegaBots as cousins. “We’re the smaller, anyone-can-get-into-it league, and MegaBots is the next level up.’’

One direction for the future of entertainment is that it will be dominated by videogames, movies, and immersive virtual reality, which can all be enjoyed without leaving home. But the founders and backers of MegaBots are betting that in-person events will still have pull.

“People want reasons to come together and have fun and cheer,’’ Adler says. “I don’t see how giant robot battles can fail.’’

Scott Kirsner can be reached at kirsner@pobox.com. Follow him on Twitter @ScottKirsner.