Dr. Geraldine Masters is the main antagonist in the 1973 horror film Don't Look in the Basement (alternately known as The Forgotten).
She was portrayed by Annabelle Weenick (as Anne MacAdams)
Dr. Masters appears to work in Stephens Sanitarium, where patients freely act out their realities in the (doctors') hopes that they will recover on their own. However, she is in fact a patient of the sanitarium, having been allowed to play out her fantasy role as a doctor—when the real doctors are murdered by other inmates, "Dr." Masters assumes control of the sanitarium and brutalizes patients who disobey her or threaten to expose her to the new nurse, Charlotte.
When Charlotte learns that Masters is not a real doctor, Masters barricades her inside the sanitarium and manipulates the other patients to help catch and murder her. The sanitarium quickly falls into chaos and Judge, an axe-wielding patient, corners and murders Masters.