A Florida Checkers employee allegedly shot and killed a customer in a fight over missing mayonnaise, according to authorities. Fast food server Elijah Mackey, 23, allegedly shot 40-year-old customer Wesley Robertson late Wednesday after Robertson complained about his order at the drive-thru window in a branch in Kissimmee, the Osceola County Sheriff’s Office said. A witness told deputies the incident was sparked by missing packets of mayo, according to his arrest warrant. Mackey allegedly climbed out of the drive-thru window, called Robertson a slew of insults, then pulled out a gun and shot him in the chest, the warrant said.