Spider Germs are the antagonists of the Doctor Who episode Kill the Moon. They are bacteria-like creatures that take on the appearance of spiders and lived on the surface of the Moon which was actually the eggshell for a giant dragon-like creature. The creatures main food source came from feeding off the creature growing inside the Moon similar to the bacteria on Earth.

In 2049, a group of astronauts arrive to destroy the Moon with nuclear bombs as it's increased gravity was causing chaos on Earth. Whilst there some of the crew were killed by the Spider Germs. They can't see good so they sense movement to attack. the However due to being like bacteria, the creatures could be killed by disinfectant spray as Courtney Woods was able to kill one with a bottle of the spray.