Out of all the monsters ever thought up which one would you least like to see come to life?

Hmm. I think the markers from the dead space series. There’s lots of scary things, but an object that gives an unlimited power source but is used to corrupt organic things into necromorph’s which are just monsters used to kill more things and turn them into necromorphs and then eventually devour all organic life on a planet is terrifying. Maybe because it’s on an extinction level, but just like the games I don’t think humanity would be smart enough to not want to use these things to try to advance our technology.