Well this is a tough question! There’s just so much competition for the title!
Immediately the monster Monsanto comes to mind. Yep, they get my title for their destruction of our nature and health via, e.g. Glyphosate, their GMOs, trying their best to own & patent seeds, etc… just these three are enough!
Did you know that their GMO seeds can produce their own toxins (pesticides) and that if you eat their stuff this process can continue within your bodies? Yep, their GMOs wreck your gut flora. Now isn’t that just nice of them!
But, there are other monsters out there. Too many to list though.
When I think of this ….. the Matrix really is not all, but indeed full of evil.