Down at Pinehurst 2, German golfer Martin Kaymer is making his own kind of history. After two rounds at the U.S. Open, he’s shot 11 birdies, only one bogey, and shot back-to-back scores of 65. How good is that? Good enough for 10 under par, the lowest 36-hole score in U.S. Open history, and a comfy lead over the rest of the field. But comfy, in golf, can vanish after a few bad breaks, so there’s more reason than ever to watch Kaymer to see if his unflappable play continues, or if it becomes… flappable.