Mark Cuban has done something he never thought he would do: He went in on a deal with Kevin O'Leary.

Cuban has sparred numerous times with O'Leary, most memorably when he threatened to revoke an investment offer in a fishing company if the founder even listened to an offer from "Mr. Wonderful." But on Tuesday's episode of Shark Tank, Cuban made a joint deal with O'Leary to the founder of Extreme Sandbox, a heavy-equipment playground for adults. 

The sharks found the concept nearly irresistible. "I always wanted to crush a car," O'Leary said.

The two sharks offered founder Randy Stenger $150,000 for 20 percent of his Hastings, Minnesota-based company. Customers pay about $300 to play with construction equipment in a giant sand pit. Clients can drive an excavator, operate a bulldozer, or crush a car (for an extra $100) for up to 7 hours.

Stenger, 39, said the company has had just under $1 million in sales since it was founded in 2012. But he said he needed $100,000 to $120,000 to open a second location.

Sharks Lori Greiner and Robert Herjavec had concerns about how Stenger would scale. 

"I didn't like the fact that you're going to open up one location," Herjavec said. "I would have liked to hear you say, 'For $150,000, we're going to open up four locations.' "

O'Leary struck first, offering Stenger $150,000 for 20 percent of Extreme Sandbox. He said that his contacts in Boston could help Stenger expand. But Cuban jumped back into the fray, saying he liked the concept, and that he owned land in Dallas, where Stenger was looking to expand.

"If you can convince Kevin to let me come in half on his deal, then I'll do it," Cuban said.

"I'll do that deal," O'Leary replied. "The land matters. And obviously Mark knows a lot of guys in Dallas, and that helps. I know a lot of guys in Boston, I'd like to set one up there too."

Multi-shark deals aren't unheard of--but O'Leary and Cuban don't go in on deals together often. Cuban and O'Leary didn't responded to requests for comment.

Stenger told Inc. he was just focused on getting a deal, and he hadn't really entertained the possibility of getting a deal from multiple sharks.

"As an entrepreneur, your business is kind of your baby--and I've watched the show long enough to know that some people will get told they have an ugly baby," Stenger said. "What was satisfying to me, whether or not I got a deal, was that the Sharks loved the concept."

Stenger says that Extreme Sandbox plans to open up another location in Pottsboro, Texas in the spring. Should that launch go well, he plans to open two locations in 2017 and three to four the following year.