Burger Boy Seongsu Naknak is a hamburger restaurant in Seongsu that serves handmade burgers and french fries. A set comes with a burger, french fries, cola, and coleslaw, and soda refills are self-service. Orders are placed by QR code at the table or at a kiosk, and camping outdoor gear is displayed in the open store. There are doors on both sides, so wind enters and the store gets cold each time a door opens.