The day's rounds - half the field had to finish the first before beginning the second, because of Thursday's weather - were defined by a kind of perplexed scowl. It was the expression that flashed across every player's face after some putt did the opposite of what he expected on the ever-faster greens.
"Watching the telecast," Tiger Woods said, "I hadn't seen this many guys blow putts past the hole with bad speed. And it's just because . . . the ball is really flying and it's tough. They made it really hard."
"We didn't think they were going to be as severe as they are," Woods said.
"I think some of the pins you can take on, and some of the pins if you miss, you miss badly," Billy Horschel, owner of the top second-round score, said. "You pay the price for it."
They weren't complaining. It was more like they needed to share after experiencing a trauma. These guys know courses and conditions and clubs as well as they know their names. They have played all over the world, on every kind of course.
But the USGA gremlins were particularly mischievous at Merion.
"You could set Merion up to where 10-over par would win and you could set Merion up to where 10-under would win," Jim Furyk said. "It depends on how they set the golf course up. And they were very protective of it. I think where they hid the pin placements, how they backed the tees up on some of the longer holes, I felt like they were definitely protective of par."
With drenching rain all week, there was a lot of pretournament talk about the course playing easy. Ernie Els predicted a four-day birdie festival. The media, including your humble narrator, picked up on that.
"It was you guys saying that," McIlroy said. "You must be very good golfers."
But it wasn't just the "you guys" in the media. It was the gremlins in the USGA. Executive director Mike Davis talked Wednesday about the impact of the weather on the course. He stressed that the USGA didn't care if everyone was under par, as long as it was a competitive tournament. Two days later, Woods was asked if he bought that.
"No," he said.
The USGA couldn't control the weather or change Merion's fairways and unforgiving rough. The one thing it could control was where the holes would be, and that revealed the gremlins' true intentions.
"The pin spots are quite tricky," Masters winner Adam Scott said. "They're on some pretty severe slopes [which] makes putting quite tricky. There's no letup."
That is the cruelest twist. By the time the golfers get to the slanted and enchanted greens, they have already been through a torture test. The tee placements and yardage are forcing them to choose irons instead of using their trusty drivers. The fairways cruelly funnel rolling balls toward the rough. If you land in the rough, or even on the wrong side of the fairway, geometry makes the green unreachable.
Mix in the weather - it went from cold to hot, wet to dry, still to windy over the course of Friday - and you get some idea why no one could get more than a few strokes under par.
And if the USGA gremlins were especially cruel with their pin placements, the end result is exactly what everyone was hoping for: a tournament that will be extremely competitive on Sunday.
"You feel like you should be 2 or 3 under par," McIlroy said, "but it's not just you that's struggling out there. It's everyone else. It's just one of those places where par is a great score."
Contact Phil Sheridan at email@example.com. Follow on Twitter @Sheridanscribe.