Laiderplacker

The  were a race of bat-like aliens that wished to invade the earth in 1938. They had weapons that worked on shooting radiation into the intended victim. One set landed in September 1938, which was a breeding party, and another a month later to find out what happened to them. They planed to destroy the world, but the Eighth Doctor managed to convince them that there was another invasion happening at the same time by using Orson Welles' broadcast. (AUDIO: Invaders from Mars)