It is the province of cartoons and the often-bumbling bad guys in ridiculous capers, those who have no idea that they are displaying the most suspicious form of motion perhaps ever taken. The Pink Panther is the king of slink. So, too, it seems, is one improbably successful thief who stole a Banksy piece, “Trolley Hunters,” from a temporary gallery space in Toronto on Sunday, June 10 at 5:04 in the morning.