snake in one's bosom
see viper in one's bosom.
“In Case Of” vs. “In The Event Of”: Which One Is Correct?Do you break the glass in case of emergency or in the event of emergency? The phrases in case of and in the event of are both prepositions.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.