Did I mean to do that? is an achievement exclusive to the Simian Flu DLC.
How to get this achievement?
Use Ion Surge as the artificial gene when trying to acquire this symptom. When a pop-up appears saying a new viral drug is being tested in a Gen-Sys lab, evolve Simian Neuro-genesis. When a pop-up is acquired stating the Gen-Sys lab was destroyed, devolve Simian Neuro-genesis (Should cost nothing). A pop up then appears stating that the evolution was reversed, causing apes' brains to shut down, killing all intelligent apes in the game.