Brad Pitt had inventive ways to bond with the kiddie co-stars of his zombie movie “World War Z.” “We went to this . . . pond with ducks,” said Abigail Hargrove, who plays Pitt’s daughter in the scary flick. “We decorated little zombie cookies. We’d break off their arms and legs and put red icing on them.” Hargrove also told us, “We were filming a scene where I have an asthma attack, and after they called ‘cut,’ [Pitt] would start singing a song he made up, called ‘Super Asthma Guy.’ ”