Story related, can't be missed.
During Chapter 13: Connecting the Strands. You must lead Atrocity into the middle and exit the chamber. Gas will fill the room and you can go back in and get a sample with . Do it again, but now you will have to web shoot the tentacles in your way. Once the doors close, you will have to shoot the tentacles on Atrocity to let the doors shut. Repeat one last time, which is very much like the 2nd time but without the initial tentacles. You will unlock the achievement at the start of the following level.