phantom menace

Translations
мнимая угроза
The economic downturn was a phantom menace, worrying investors unnecessarily.
Экономический спад был мнимой угрозой, беспокоя инвесторов без необходимости.
Definitions
A hidden or unseen threat; something that causes fear or concern but is not immediately visible or obvious. The phrase is also widely recognized as the title of the 1999 Star Wars film 'Star Wars: Episode I – The Phantom Menace.'
Words
phantom

adjective
призрачный
menace

noun
угроза