The Zygons are a race of alien shapeshifters, allowing them to replicate the appearance of another being, who try to seize power on other planets after their homeworld was destroyed. One of their ships, commanded by warlord Broton, crashed in ancient Loch Ness. They used a Skarasen, that provides milk for their sustenance and which had become known as the Loch Ness Monster by humans, to attack an energy conference in London. The plan was foiled by the Doctor and UNIT and the ship was destroyed.