The Flood (Doctor Who)

The Flood is a sentient virus imprisoned in a glacier on Mars thousands of years ago. It was later released by the crew of Bowie Base One, humanity 's first Martian colony. The Flood's release and spread would later cause the colony's destruction killing everyone in it ( however three survived thanks to The Doctor ). An infection of The Flood is charaterized by cracks on a host's upper lip mouth with water dripping from it, a major change in the voice of a host, and the ability to shoot water from their hands. A common vocal noise for an infected individual is a raspy growl, which a voice can still distingush who he/she is. The latter one is how they can spread the virus.

According to the Doctor, the Flood is a paitent and intelligent pathogen that has time as an ally. This thing is an extreme danger to any lifeform in the galaxy because it takes one drop in a world's water supply for it to take contol of a planet. However, like other threats in the galaxy it has many weaknesses and flaws. Electricity is a good weapon because it and water are a bad combination. Nuclear explosions are also good since it was demonstrated by the martian colony. Freezing temperatures are also injuring aganist it since ice imprisions them. After the destruction of the base however there is a chance of it returning due to the amount of glaciers on Mars. It is possible that it might be on other worlds.