Hillary wasn’t the only one New Yorkers lined up for in spades today: over in Madison Square Park, David Chang was on hand to unveil Momofuku’s very first hamburger at Shake Shack.

When we got there shortly after noon, 700 of the 1,000 one-day-only patties had been sold, according to Mark Rosati, Shake Shack’s Culinary Director. “This is the longest line we’ve ever had at Shake Shack,” he said, adding that there were only about 10 people in line around 9 a.m. but it “exploded” within twenty minutes, quickly growing to a size that was comparable to “a good day for us in the summertime.” And it only grew from there.

To pump up the crowd, some of whom waited two hours for a taste of the Momofuku Shrimp Stack, Chang and some of the Shack’s line cooks left the kitchen to give out high fives:

“New Yorkers are a pretty jaded bunch,” Chang told us. “When they line up for something, hopefully we exceed those expectations.”

Here’s Chang describing the burger:

Asked if the Shrimp Stack will find its way onto Momofuku’s menu, Chang said it was likely a one-time thing, but you can still try burgers created by Andrew Zimmern, April Bloomfield and Daniel Humm (plus a day of live performances on Thursday) as the Shack’s 10th anniversary celebrations continue this week.