In your opinion, what is the worst thing mankind has ever invented?

Guns, drugs, cars, the internet? Even things that were made with good intentions but now cause issues and misery for people/planet?

My opinion- non-biodegradable plastics. Yes plastic has it’s uses and has made our modern life completely different in terms of food storage and transportation, cosmetics, use in machines and so forth. Pretty much everything we use day to day has plastic in it. However it is also ruining our planet, so I would say that plastic is a double edged-sword and is one of the worst things invented right now (also lack of awareness and care about how plastics can be dealt with after use is also a big factor in this). For the record I’m no eco warrior but I try my best when it comes to plastic, recycling where I can etc

Thoughts?