Disguise

The chameleon circuit provided TARDISes with a disguise which allowed them to blend into their surroundings. The Doctor's TARDIS was disguised as a police box in 1963, and was left stuck in this form as the chameleon circuit broke down. (TV: An Unearthly Child)

Skin suits were disguises which were used most notably by the Slitheen family. (TV: Aliens of London/World War Three)