Mad honey
Good question. Is it a war crime to poison invading troops? Is it biologic warfare to catapult diseased animals into a besieged castle? To booby trap bodies? War is nasty and full of gray.
Russia invaded without any reasonable reason. That right there is the war crime.
I struggle with this too. Someone breaks into my home I legally have the right to kill them. Not sure if how I do it matters.
Indeed, in 67 B.C. Roman soldiers invaded the Black Sea region under General Pompey’s command, and those loyal to the reigning King Mithridates secretly lined the Romans’ path with enticing chunks of mad honeycomb. The unwitting army ate these with gusto, as the story goes. Driven into an intoxicated stupor by the hallucinogenic honey, many of the flailing soldiers became easy prey, and were slain.
https://modernfarmer.com/2014/09/strange-history-hallucinogenic-mad-honey/