Anyone who's seen more than a few episodes of Shark Tank over its nine seasons knows what to expect from the investors. You’ve got people like cool uncle Mark Cuban, pint-sized ball of energy Barbara Corcoran, and the always laid back Robert Herjavec. But Kevin O’Leary’s image isn’t quite as positive as his cohorts' — in fact, his “Mr. Wonderful” nickname doesn’t really make sense.

The Canadian businessman has sort of become the Simon Cowell of Shark Tank — he's blunt, sarcastic, and always looking at the bottom line. It might be easy to write off Kevin when he offers up those unsexy licensing deals, but you can’t deny his success co-founding companies like former software giant Softkey and mutual fund O'Leary Funds. That still doesn’t explain the nickname, but we’ll turn to the man himself for that story.

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From left: Mark Cuban, Barbara Corcoran, Daymond John, and Kevin O’Leary.

Kevin has told a few variations of how the moniker came to be, but they all go back to co-star Barbara. You see, he and his castmates don’t really recall how it started — in fact, they’re “still trying to find the tape” from the moment they think it happened in Season 1. “You know, it might have been Barbara. She flew in on her broom that morning and she was in a nasty mood. That’s what happened,” he joked to Entertainment Weekly.

He later confirmed that it was Barbara who coined the name while the the two were negotiating a difficult deal in 2009. “Barbara said, ‘Well aren't you Mr. Wonderful?’ and I said, ‘You know what Barbara, I am!’” he told Boston Magazine. And it stuck — so much so that people rarely call him Kevin anymore. He continued, “I show up at hotels and my reservation is under the name Mr. Wonderful. They don’t even know my real name. That’s just nuts.”

The multimillionaire embraces the persona when he’s being pitched by business owners. “If they think it's tough in the Shark Tank, wait until they get out in the real world," he told Business Insider. “If they can't take a guy like me, then they're not ready.”

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It’s not just about the entrepreneurs themselves, however — Kevin doesn't want to waste his time on something that won't make a profit. “I tell the truth and the truth sometimes hurts, but it's still the truth,” he's shared. “I look at it this way: I prefer deals where I have control, 51 percent. And I give the entrepreneur anything they want in terms of setting the metrics… Put some milestones out there. If you reach them, you stay running the business. If you don't, I whack you and I put somebody else in place because they still own their stock and I want to get my money back.’”