The Dink Network

It does look like a fire lake. As for why it's there... Beats me! My first thought was maybe they were just testing the fire tiles when Seth screenshotted the map, but on second thought, that would be a really weird place to test something (a finished screen in the game world proper).

Also, hilariously, there's a giant desk at SunCool pond. That's just a blocker to keep Dink from venturing there too early, and is actually invisible in-game.