Mutant (Revelation of the Daleks)

A mutant was a product of Davros's experiments on Necros.

Biography
The mutant attacked the Sixth Doctor before Peri Brown beat him repeatedly with a club-like stick to save the Doctor.

He was mortally injured but, before he died, forgave Peri and told the Doctor that the Great Healer had used him as a genetic experiment. The mutant's appearance and hostility were caused by the experiments. (TV: Revelation of the Daleks)