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, and killed anything they saw. The Sevateem created a wall of mild sonic disruptors that protected them from the Phantoms, but they would still kill anyone who strayed from the settlement. Some attacked the Doctor and Leela. The Phantoms were presumably destroyed when Xoanon was fixed. (DW: The Face of Evil)

Phantoms were creatures of myth on Earth. In his speech to the Clerics in which he told them that the Doctor was a living breathing man, Colonel Manton said that the Doctor was not, among other things, a phantom. (DW: A Good Man Goes to War)