Exxilon antibody

The Antibodies were artificial creatures created by the Great City of the Exxilons to protect itself.

History
Many Antibodies were created when the Third Doctor, Bellal and the Daleks invaded the city, but they were destroyed along with the city.

The Antibodies were capable of resisting the bullets of the machine-guns the Daleks had substituted for their main weapons. (TV: Death to the Daleks)

Behind the scenes

 * The Antibodies were played by Terry Walsh and Steven Ismay, who were uncredited on-screen but credited as "Zombies" in Radio Times for part four.