Walk into the lone Chicago Wal-Mart to stock up on pop in the summer heat and there, rising like a palm tree in an oasis, is a stack of Coke cases at a special price: 24 cans for $5.

A brand-name beverage like Coca-Cola for about 20 cents a can is more than a great deal. It’s a sign of Wal-Mart’s purchasing might, a warning shot to competitors and less than good news for the beverage industry.

Experts call that kind of intimidating power “disruption,” and it will come to the Chicago area in a bigger way now that Wal-Mart plans to open a second store in the city, on its way to what it hopes will be dozens more urban locations.

Water is free. And won’t make you fat. Or give you diabetes.