The attorney for “Slender Man” defendant Morgan Geyser isn’t specifying the basis for the appeal she filed Monday in her case. Geyser and Anissa Weier were both committed to mental health institutions for a stabbing attack on a classmate four years ago. Payton Leutner survived 19 stab wounds. Geyser entered a guilty plea to attempted first-degree intentional homicide charges last year to avoid prison. Her sentence involves spending the next 40 years in a mental institution.