Answer
Vince McMahon represented Umaga in the "Battle of the Billionaires" WrestleMania 23 match. This was a match between McMahon and Donald Trump, where each billionaire had a wrestler representing them. If McMahon's wrestler won, he would get to shave Trump's head, and if Trump's wrestler won, he would get to shave McMahon's head. Umaga won the match for McMahon, and McMahon shaved Trump's head in the post-match ceremony.