Phantom

Phantoms were the name given to strange, blind projections created by Xoanon's id. The Phantoms were glowing, orange lights. They were attracted to sonic energy, killing anything they saw. The Sevateem managed to create a wall of mild sonic disruptors that protected them from the Phantoms, but they would still kill anyone who strayed from the settlement. The Doctor and Leela were attacked by some. The Phantoms were presumably destroyed when Xoanon was fixed. (DW: The Face of Evil)