Alter Image
From Wookieepedia, the Star Wars wiki.
Alter Image was a Force power developed by Hyobu Sulloran which allowed the user to alter his or her own personal features, such as the height, weight, skin color, facial features, sex, voice, and body shape. These changes would stay as long as the Force-sensitive kept the power up, but would be dropped whenever the Force-user fell unconscious or simply lost concentration. However, other Force-sensitives skilled in receptive telepathy had a chance to see through this disguise which resulted in a contest of skills between the two Force-users. The power became more difficult to use the less the Force-user knew about the person being imitated.
