Considering how his day has gone so far, perhaps yelling "Happy Gilmore" at Phil is apt. After all, he's in a dark place right now -- a fan favorite who couldn't get out of his own way while in contention early in the final round. His meltdown on the par-3 fourth was probably something Happy would've done at one point.
Or it's just an idiot in the crowd yelling things at players on the tee. It's probably this.
This is better than the constant "Get in the hole!" we hear at every tournament. And if you think about it, Phil's following is not unlike that of Happy Gilmore anyway. Remember the fan doing a cannonball into a lake after he drained a putt? Or the one that rolled down a hill earlier this year? His life really is the movie.