John liked to sneak up on people. Sometimes he'd simply say "Boo!" and laugh. This could escalate to grabbing your shoulders with a non-threatening, "I got you!" Some were more invasive than others, and you'd remember if you were on the receiving end of one of those. The main thing was to maintain situational awareness whenever John was nearby. You avoided situations and places that left you vulnerable to his sneak attacks.
To John, the line between reality and fantasy was permeable. For example, he had puppets. He knew they were inanimate and how they operated. But he didn't think ventriloquist dummies were puppets, just weird-looking people. So it made perfect sense to put his hand on someone's back and do his act. He perfected the gag of drinking water while the "dummy" kept talking. And as this picture demonstrates, he was a master of eyeball rolling.
