Indian sign

Indian sign  {n.},  {informal}

A magic spell that is thought to bring bad luck; curse; jinx; hoo-doo. — Used with "the", usually after "have" or "with"; and often used in a joking way.

Bill is a good player, but Ted has the Indian sign on him and always beats him.

Father says that he always wins our checker games because he has put the Indian sign on me, but I think he is joking.

Compare: GET ONE'S NUMBER.