A shark dragged a lifeguard underwater after grabbing his rescue buoy at Scarborough Beach over the weekend. Greg Wilfert, 71, was swimming around buoys with other lifeguards on Saturday, said he thought he’d been pulled by a boat, or caught up in a propeller, as he was taken around five feet under water. “That’s the only thing I could think of until I realized there was no boat,” he told CBS News. Greg managed to remove his strap and swim back to shore, but said the encounter was frightening. “I just swam as fast as I could to the surface, and then I just was hoping it wasn’t behind me. I could’ve beaten  Michael Phelps.” He then warned beachgoers about the encounter as another lifeguard took over – before shutting the beach down for an hour. Jet skis and drones have since been deployed to monitor the situation. “I’m taking it seriously. I won’t be swimming the buoys for a while,” he told Fox News.…