Doctor Who: EVERY NuWho Villain And Monster Ranked Worst To Best
11. The Flood
Appear in: The Waters of Mars.
Filtered water is meant to be better for you, and for the intrepid men and women of Bowie Base One, the water filters worked as a vital piece of equipment by keeping out a deadly virus. Until one day, one of them broke leading to a catastrophic chain of events so significant that it's a fixed point in time. Remember that, Doctor - whatever happens must happen.
The water zombies are a shivering sight with their frighteningly fixated eyes. But it's the actual mutation process which is the scariest part. Andrew Stone suddenly slumping to his knees, then convulsing before spinning round to a screaming Margaret Cain. Cain, herself, goes through a similar transformation and eyes up our beautiful Blue Planet on the sickbay monitor in a sinisterly lustful way.
The most painful changes we see are to the technicians, Steffi Ehrlich and Roman Groom, the former finding herself trapped, unable to escape the Flood with her final tearful moments watching a video message from her two young children; soon afterwards, the grim realisation on Roman's face says it all when a single, fatal drop hits his face. Well, you would react like that knowing you're about to turn into a crusty-mouthed, water spewing monster.