It's mean to steal someone else's candy.
It's Halloween and Franklin's run out of candy to give to the kids who visit his house, and he eyes up his son Dick's candy that Dick already brought back.
Franklin wants to keep giving candy to trick or treaters.
Franklin asks Dick which candy he doesn't like, and asks if he can use that candy to give to trick or treaters.
Franklin starts grabbing candy out of DIck's candy haul and handing them out whenever someone shows up at his door.
Dick is happy to give away candy he doesn't like anyway.
Dick notices he's missing most of his candy the following morning and starts to cry.