Metamorphosis technique

The metamorphosis technique was a Rutan technology enabling the amorphous Rutans to mimic the shape of specific individuals and impersonate them as a tactic in their war with the Sontarans. (PROSE: Blind Terror)

The technique was first developed at the start of the 20th century. The Rutan Scout the Fourth Doctor faced on Fang Rock highly trained in the new technique, impersonating key members of the lighthouse staff. (TV: Horror of Fang Rock)