soupervisor
An authority-figure --- such as a parent, older sibling/relative, school aide, etc. --- whose job it is to see that you "finish your stewed vegetables like a good little boy".
I'm all for insisting that a child "eat healthy", but I totally disapprove of a soupervisor who uses preposterous scare-tactics (like saying that the youngster's arms and legs will shrivel up and disappear if he doesn't eat his vegetables, or that Lucifer Himself will suddenly appear out of a blazing ball of fire and brimstone to devour him) in an attempt to scare said frail vulnerable pint-size into finishing his food.