Mickelson loves a good practical joke. Here's one he pulled on caddie Bones Mackay, as told by Golf Magazine senior writer Cameron Morfit:
Jim (Bones) Mackay was inching along a crowded parking lot at the 1997 U.S. Open at Congressional when one oblivious patron suddenly walked smack into the front of the caddie's car.
Phil Mickelson, sitting in the passenger seat, decided to play up the incident as if his looper had run over the hapless spectator. Phil summoned his security detail, who were following along behind, and had them call a few of their fellow men in blue, who with straight faces made a big show as if to take Mackay downtown.
"They were going to book him for a hit and run," Mickelson says, laughing. "This was like 30 minutes before we were going to tee off. Jim just went with the whole thing. He's very good about letting me play my jokes and stuff, which I like to do."
Mackay went along with the joke because he thought it wasn't a joke; Bones thought he was really in trouble. "There were a couple of very uncomfortable minutes on the range," he says.