hornet's nest
1. A dangerous, complicated situation. If we do invade, I fear that we will find ourselves in a real hornet's nest.
2. A situation that produces angry reactions. The politician's off-the-cuff remark about pollution stirred up a hornet's nest among environmentalists.
a hornets' nest
a situation fraught with trouble, opposition, or complications. 1992 New Scientist The notion of these ‘life patents’ has opened up a hornets' nest of moral, legal, social and scientific concerns.