RichThesaurus
scare the life out of
vs
scare the pants off
scare the life out of
verb
To scare something or someone to a great degree.
scare the pants off
verb
To scare or startle someone thoroughly.
How often have the words
scare the life out of
and
scare the pants off
occurred in a corpus of books?
(source:
Google Ngram Viewer
)