Early on Tuesday, Kamilah Denny was allowed to open a Christmas gift early. It was a brand new hoverboard, the hottest gift of the 2015 holiday season. She unwrapped it in her Brentwood, California, home, stepped between its two rubber wheels and, almost immediately, the toy caught fire. The battery exploded. The family was able to put out the fire before it spread beyond a nearby wall.

They were lucky. According to outside observers, water doesn’t usually put out fires for hoverboards, which run on lithium ion batteries. Only a fire extinguisher will do.

“DO NOT THROW WATER ON THE FIRE! That will make matters much worse,” warned ZDNet writer Adrian Kingsley-Hughes. He had to put together a story this week called “Tips on Buying a Hoverboard That Won’t Catch Fire.”

Because hoverboards catch fire. In their current iteration, that’s what they do. They move forwards and backwards and lean sideways and they sometimes explode.

In an Ohio home this month. In a Seattle mall last week. In what used to be a kitchen in the U.K. last month.

So how did this happen? How did a toy so combustible that airlines won’t allow them on board become the biggest toy of 2015?

According to Mark Cuban, it’s because of a patent fight.

Earlier this year, Cuban signed a letter of intent to buy the patent license for the proprietary tech behind the hoverboard from Shane Chen, who owned a brand called Hovertrax. Chen was in a patent battle to sell the hoverboard with another company called IO Hawk.John Sobastian, IO Hawk’s creator, said that he had come up with the idea simultaneously, and had already started manufacturing the boards in China. Chen, however, had the patent, and Cuban hopped on, expecting a large-scale payday come Christmas.

Meanwhile, as the patent squabble played out in court, overseas competitors started selling their hovercraft knockoffs on Amazon.

What ensued was a race to the bottom for knockoff brands, who tried to make the cheapest available product with sometimes combustible parts. Until last month, Amazon was selling hoverboards for as little as $350.

By contrast, a licensed Razor Hovertrax, which the company told BuzzFeed is being built on their “strength, which is quality and safety,” will sell for around $600 in the new year.

“Because of the uncertainty around the patents involved in making them, everyone knocked it off, which led to a group of factories making boards and trying to compete completely on price,” Cuban told The Daily Beast over the messaging app Cyberdust.

Hoverboards are everywhere. They’re the hottest gift of the holiday season, in every way. And knowing which ones are safe is almost impossible.

That’s why Cuban and Carlton Calvin, president of the Razor scooter company, are now in a race to build a safe, affordable hoverboard, backed by warranties and filled with materials that won’t spontaneously combust. As Calvin put it to Buzzfeed today, he wants to “put the genie back in the bottle.” His company’s hoverboard is available now, despite the several-hundred-dollar premium. Cuban pulled out of Chen’s patent fight in November. He relinquished his patent hold (and with it his partnership with Chen), and now he’s invested in a company that will do the same as Razor—make a reliable, fire-free hoverboard with a warranty—but with American-made parts.

(Which means he may be right about the root causes of the hoverboard blazes. But he’s not exactly an impartial observer.)

As for now? Cuban says even the best hoverboards on the market are built with “junk” parts—and experts and government-funded consumer protection agencies from both sides of the Atlantic back him up.

“There are a lot of crazy back door deals at those factories so that they all buy almost all of their components from the same few sources—which means even the most expensive have some junk in them,” said Cuban.

A national consumer protection board in the U.K. backed Cuban up last week. National Trading Standards said that 15,000 of the 17,000 hoverboards, or 88 percent, that were shipped into the U.K. were deemed unsafe and detained at national entry points.

“Our teams at sea ports, postal hubs and airports have seen a significant spike in the number of unsafe ‘hoverboards’ arriving at national entry points in recent weeks and are working around-the-clock to prevent dangerous items from entering the supply chain,” said National Trading Standards head Lord Toby Harris.

The United States Consumer Product Safety Commission says it knows of about 12 hoverboard fires in 10 states so far, including at least 40 injuries.

Cuban says the fires are just the start of it.

“They all cut corners, particularly in user safety,” said Cuban. “Put aside the batteries. If a board has enough power to ride a 250-pound person, it could create problems for a kid using it. And the software that regulates it could be awful. The circuit boards can overheat. Get the speed up and no software regulation and you can really get hurt.”

In fact, Cuban (who self-identifies as “leaning libertarian”), says if the market isn’t going to self-correct on this one, there should be a law to make sure kids are safe.

“If you see a kid without a helmet (on a hoverboard), you should arrest the parents,” he said. “You go fast, you jump off, hello head trauma.”

Although the regulations came before the spate of fires and injuries, hoverboards are banned in New York City, and users face fines of $50.

“It’s a big jump, but until there are some standards, I don’t blame the cities [for making laws to temporarily ban them],” Cuban said. “On a skateboard, you have to develop skills to get to a certain speed. On the boards, it takes a little balance to get started and it’s easy to let the board go too fast. Boom, you’re toast.”

As for those who are dead set on getting their kids a hoverboard this Christmas, is there a tip-off for which ones won’t explode?

“There’s no way to know,” said Cuban.