New York(CNN) Mark Cuban is questioning Donald Trump's ability to function independently if elected, saying the presumptive Republican nominee would be a "puppet president" hamstrung by a lack of experience and intellectual rigor.
"He would be so dependent on everyone around him because of his lack of depth of knowledge and fear of failing," Cuban told BuzzFeed News in an email interview.
"And he isn't good at hiring either," the billionaire owner of the NBA's Dallas Mavericks continued. "That's why he puts family (and he gets credit for having such smart, accomplished kids) in so many important positions."
Cuban said he likes his "thin-skinned" fellow billionaire businessman but said Trump "has absolutely zero self-awareness. None. Zip."
It's not the first time Cuban has sought to take Trump down a peg.
Asked in an interview with CNN's Erin Burnett on "OutFront" last month how smart he thinks Trump is, Cuban replied: "Probably not as smart as he thinks he is."
In an email to CNNMoney days earlier, Cuban confirmed reports that he'd been asked to consider a third party run in November, saying, "It would have been fun to run against Donald" but that it was "too late" to enter the race.
Earlier that week, Cuban offered a gathering of of hedge fund professionals at the SALT conference in Las Vegas his outline for defeating Trump in the general election.
First, he said, Democratic front-runner Hillary Clinton should choose a bombastic running mate, "someone like me who would just throw bombs at Donald" -- a job Cuban said he would consider if he was allowed to rip and ridicule the Republican.
But Cuban has also criticized Trump in more stark terms, telling Burnett during their conversation that a Trump victory in November could lead to a "huge, huge correction" in the stock market.
"That uncertainty, potentially as the president of the United States, that's the last thing Wall Street wants to hear," he said.