Elon Musk's Boring Company sold out of 20,000 limited-edition flamethrowers in just four days earlier this year.

On the "Joe Rogan Experience" podcast on Thursday, Musk said that the product was "dangerous" and "wrong" but that people didn't care.

"Don't buy it, that's what I said," Musk joked. "But still, people bought it. There was nothing I could do to stop them."

Elon Musk has said that flamethrowers sold by The Boring Company were "a terrible idea" and that he tried to tell people not to buy them before selling 20,000 machines in just four days.

On the "Joe Rogan Experience" podcast on Thursday, the host Joe Rogan asked Musk whether the Boring Company CEO had ever considered selling the flamethrowers dangerous or thought doing so could make the company liable for any incidents.

"Yeah it's a terrible idea," Musk replied. "You shouldn't buy one. I said don't buy this flamethrower. Don't buy it. Don't buy it, that's what I said. But still, people bought it. There was nothing I could do to stop them. I could not stop them. I said don't buy it, it's a bad idea.

"It's dangerous, it's wrong. Don't buy it. Still, people bought it. I just couldn't stop them."

You can watch the interview below. Musk talks about the flamethrowers at 1:22 in the clip:

Musk did tell people not to buy the devices in January, but he also hosted a pickup party for the first 1,000 customers when they went on sale in June. At the time, he tweeted enthusiastically about the machines, generating more publicity for them.

The Boring Company is a tunnel-construction company working on high-speed transport systems, yet it is also known for its limited-edition merchandise, such as the hats it sold in 2017, and typically does not sell more than one product at a time.

"We did 50,000 hats and that was a million dollars," Musk told Rogan. "And we said OK, we'll sell something for 10 million. And that was 20,000 flamethrowers at $500. They went fast."

He said he was inspired to sell the flamethrowers after watching the 1987 film "Spaceballs."

"I’m a big fan of 'Spaceballs' the movie, and in 'Spaceballs,' Yogurt goes through the merchandising section," he said. "And they have a flamethrower in the merchandising section of 'Spaceballs.' It was like, we should do a flamethrower."

The flamethrowers sold by The Boring Company. The Boring Company

The machines are officially called Not-a-Flamethrower, owing to shipping and customs regulations that restrict the transport of anything termed a flamethrower.

"To be totally frank, it's actually just a roofing torch with an air-rifle cover," Musk told Rogan. "It's not a real flamethrower. We were very clear. This is not actually a flamethrower."

Despite this, Musk often refers to the machines as flamethrowers on Twitter and in interviews.