Metamorpho, the Element Man!
Metamorpho is a shape-shifting persona adopted by Rex Mason after prolonged exposure to an ancient Egyptian artifact (first appearance, The Brave and the Bold No. 57, Dec 1964/Jan 1965: "The Origin of Metamorpho!"). Also known as "the Element Man", he can adopt others' abilities and shape and morph into all types of elemental forms - but he is also disfigured and must wear a mask to preserve a sense of his original appearance.
Metamorpho appears in the chronicles as the true savior of an important scientist, before even Superman or Batman are able to free him (WF No. 226, Nov/Dec 1974: "The Freak Who Never Fails!"). He is one of the few heroes who turns down an offer of membership in the Justice League of America though he later joins Batman's group, The Outsiders.