American performer who wore the suit of Armus, the malevolent creature that kills Tasha Yar, in the Next Generation episode Skin of Evil, and later played a Sheliak.
Mart McChesney (1954 to 1999) was an American actor who performed two heavily costumed roles in The Next Generation.
In the first-season episode Skin of Evil he is the physical performer of Armus, the oily black entity on Vagra II that kills Tasha Yar. The part required him to be submerged in a pool of dark liquid and to rise out of it in costume, while the voice of Armus was supplied by Ron Gans.
He returned in the third-season episode The Ensigns of Command as the Sheliak who deals coldly with Picard over the removal of the colony on Tau Cygni V.