Trump has been a major supporter -- and participant -- in World Wrestling Entertainment since the late 1980s, when the company held matches at Trump Plaza in Atlantic City.
For years, Trump was a ringside regular, and in 2007, he climbed in himself. In 2007, Trump challenged WWE owner Vince McMahon to a proxy bout: The loser lost his hair.
McMahon's wrestler was defeated, and Trump gleefully shaved McMahon's head.
Later, Trump was inducted into the World Wrestling Entertainment Hall of Fame.
Along the way, Trump learned a lot that has suited him in his White House run.
Like how to get supporters excited:
How to trash talk:
How to take your opponent down:
And perhaps most importantly, how to take a hit: