So you we all know about the grey goo scenario but what if we took a spin on this. here's how it goes in my head. Someone designs a virus that makes turtles able to digest garbage, well long story short is the entire ecosystem go's to crap once the virus evolves to infect other things and pretty soon all the biomass on the planet becomes these deformed versions of their previous forms and all life on the planet evolves to either produce some form of toxic garbage or eat said garbage which then forces humans to try and inject themselves with the retrovirus but find it will never affect them for whatever sciencey reason, so instead they design a new virus that splices human dna with cockroaches and the whole of humanity evolves into humanoid roaches.
