Alvarian space wyrms were a type of spaceborne creature. They were gigantic, worm-like creatures, with fins down their sides and tentacles around the heads. They had a low-range, telepathic hive mind, allowing them to control others.
The Second Doctor, Jamie and Zoe were once trapped on a space station which was entangled with an Alvarian space wyrm. It stopped all incoming spacecraft and controlled a group of snake-like aliens, ordering them to attack the station. The Doctor was able to put some of the snakes to sleep using his recorder. He, Jamie and Zoe went to the communications array and reprogrammed it, allowing the Doctor to play music directly into the Alvarian space wyrm's brain. The wyrm and all the snakes it controlled went to sleep. (COMIC: The Forgotten)