stir up a hornets' nest - Phrases/Idioms
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Make trouble, cause a commotion, as in Asking for an audit of the treasurer's books stirred up a hornets' nest in the association. This metaphoric term, likening hornets to angry humans, dates from the first half of the 1700s.