deform — If something deforms a person's body or something else, it causes it to have an unnatural shape. In technical English, you can also say that the second thing deforms.
distort — to twist awry or out of shape; make crooked or deformed: Arthritis had distorted his fingers.
maim — to deprive of the use of some part of the body by wounding or the like; cripple: The explosion maimed him for life.
mar — to damage or spoil to a certain extent; render less perfect, attractive, useful, etc.; impair or spoil: That billboard mars the view. The holiday was marred by bad weather.
mutilate — to injure, disfigure, or make imperfect by removing or irreparably damaging parts: Vandals mutilated the painting.