boogeyman
/ˈbuːɡiːmæn/Definitions
1. noun
a mythical creature or personified embodiment of a child’s fear or nightmare; a monster or ogre that is used as a threat to discipline a child
“As a child, she was terrified of the boogeyman, but now she realizes it was just her parents making up a story to scare her into behaving.”
2. verb
to frighten or intimidate someone by describing a mythical creature or person
“The mother boogeyman-ed her kids by telling them about a monster that lived under their bed.”