Octopus pants, or, who is Billy Horschel, and what’s he doing dominating at Merion?

One player at the U.S. Open set a record Friday that will never be beat.

Not Tiger, not Phil, not Rory. No, it was Billy Horschel who came from out of nowhere, sort of, to lay down a historic round. Horschel hit all 18 of Merion's greens in regulation, an astonishing feat when you consider that the U.S. Open is designed to expressly prevent that kind of course-throttling.

[Related: Phil Mickelson takes lead at U.S. Open playing his way]

"I think some of the pins you can take on, and there are some pins if you do take on and you miss, you miss badly. You pay the price for it," Horschel said afterward. "I was pretty happy if I hit [to within] 20, 25 feet. If I made the putt, I was happy with it. And there's some other pins you can go more aggressive and get it a little closer."

Horschel carded a three-under 67, giving him a one-under total for the first two days and the clubhouse lead. So, with the preliminaries out of the way, let's take a look at Mr. Horschel and how he found himself atop the leaderboard at the toughest golf tournament of the year.

Horschel, age 26, won his first PGA Tour event this season at the Zurich Classic in New Orleans. He's got a solid golf pedigree; his score of 60 at the 2006 U.S. Amateur is a record at a USGA tournament.

As PGATour.com noted, Horschel had a bit of a temper problem earlier in his career. Two years ago, he had a full-on club-throwing fit at the McGladrey Classic. Soon afterward, he hired a sports psychologist, and perhaps not coincidentally, his career has skyrocketed. He earned his 2013 card through Q School, and has played his way into golf's most elite tournaments.

Oh, and then there's the matter of the Octopus Pants. Sponsors announce in advance the outfits each player will wear at majors, and release this "scripting" the week of the event. CBS Sports noted that Horschel will wear Ralph Lauren's Octopus Pants on Sunday, and we say that in itself is reason enough to tune in. If he wins the tournament with those? Best fashion moment in golf since Tiger started wearing the red and black.

Before then, though, he's got work to do. The course setup will only get tougher, and Horschel will need to remain patient for the next 36 holes. He's already proven he belongs; here's where we find out how long he might stick around.

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• Tiger Woods has an injured elbow, but remains in U.S. Open contention