Donald Trump. Mark Cuban. The Twitter war of the Billionaires is on!
The beef started with Cuban offering Trump $1 million to shave his head in a response to Trump's $5 million offer to President Obama to produce his college transcripts.
That was November, and the Smart Phone Smackdown has only intensified since. Last week on the Tonight Show, the Dallas Mavericks owner stoked the flames.
Cuban produced a letter he received from Trump in 2004, when his show The Benefactor, an obvious takeoff on Trump's The Apprentice, had just been canceled.
In that letter, Trump wrote to Cuban: