Or why Runner couldn't melt that big ass door in AC
Even though it retroactively presents some logical issues I do agrre with Corporal. It's extremely usefulc ability and ever Xeno should be able to do it. And it can't be restricted to DNA reflex. Let's take Runner from Alien 3 - it was born from dog/ox - neither of these animals are able to spit out their blood or any other kind of liquid for attack as far as I remember