He hides behind doors. He creeps quietly down the hallway to the kitchen. He waits patiently on the far side of the refrigerator, not making a sound, hardly breathing, waiting for his opportunity to say, "I'm just trying to keep your skills sharp." Someday, he may be asking why I'm having a heart attack.
He parks outside my office when he thinks I should be home by now, then leaves suddenly when he notices I have seen him. I ask him him why he didn't come in, why he didn't simply call. He stares at me as though I have done something wrong.
He is practicing his own skills. The Stalker.